This is the report, bold is my logging steps in the process:

DELETE core-cbnl-20140901.xml

Improper use? Potential bug? Your feedback is welcome:
Contact: basex-talk@mailman.uni-konstanz.de
Version: BaseX 7.7.2
Java: Oracle Corporation, 1.7.0_15
OS: Windows Server 2012, amd64
Stack Trace: 
java.lang.ArrayIndexOutOfBoundsException: 372
	at org.basex.io.random.TableDiskAccess.flush(TableDiskAccess.java:124)
	at org.basex.data.DiskData.finishUpdate(DiskData.java:212)
	at org.basex.core.cmd.Add.run(Add.java:109)
	at org.basex.core.Command.run(Command.java:345)
	at org.basex.core.Command.exec(Command.java:321)
	at org.basex.core.Command.execute(Command.java:78)
	at org.basex.server.LocalSession.execute(LocalSession.java:122)
	at org.basex.server.LocalSession.execute(LocalSession.java:114)
	at org.basex.server.Session.execute(Session.java:50)
	at org.basex.http.rest.RESTCommand.run(RESTCommand.java:40)
	at org.basex.http.rest.RESTPost.run(RESTPost.java:108)
	at org.basex.http.rest.RESTServlet.run(RESTServlet.java:14)
	at org.basex.http.BaseXServlet.service(BaseXServlet.java:58)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:51)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100)
	at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:953)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
	at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1041)
	at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:603)
	at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.doRun(AprEndpoint.java:2430)
	at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.run(AprEndpoint.java:2419)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
	at java.lang.Thread.run(Unknown Source)

 ADD "C:\Servers\xslweb\home\webapps\CBNL-browser-v2\work\contexts\core-cbnl-20140901.xml"
 CREATE INDEX ATTRIBUTE (2d) Database 'CBNL' is currently opened by another process.
 CREATE INDEX TEXT (2e) Database 'CBNL' is currently opened by another process.
 CREATE INDEX FULLTEXT (2f) 

Improper use? Potential bug? Your feedback is welcome:
Contact: basex-talk@mailman.uni-konstanz.de
Version: BaseX 7.7.2
Java: Oracle Corporation, 1.7.0_15
OS: Windows Server 2012, amd64
Stack Trace: 
java.lang.RuntimeException: Data Access out of bounds:
- pre value: 0
- #used blocks: 0
- #total locks: 0
- access: -1 (0 > -1]
	at org.basex.util.Util.notexpected(Util.java:53)
	at org.basex.io.random.TableDiskAccess.cursor(TableDiskAccess.java:488)
	at org.basex.io.random.TableDiskAccess.read1(TableDiskAccess.java:189)
	at org.basex.data.Data.kind(Data.java:282)
	at org.basex.query.value.node.DBNode.<init>(DBNode.java:53)
	at org.basex.core.cmd.OptimizeAll$DBParser.parse(OptimizeAll.java:201)
	at org.basex.build.Builder.parse(Builder.java:73)
	at org.basex.build.DiskBuilder.build(DiskBuilder.java:90)
	at org.basex.core.cmd.OptimizeAll.optimizeAll(OptimizeAll.java:126)
	at org.basex.core.cmd.OptimizeAll.run(OptimizeAll.java:44)
	at org.basex.core.Command.run(Command.java:345)
	at org.basex.core.Command.exec(Command.java:321)
	at org.basex.core.Command.execute(Command.java:78)
	at org.basex.server.LocalSession.execute(LocalSession.java:122)
	at org.basex.server.LocalSession.execute(LocalSession.java:114)
	at org.basex.server.Session.execute(Session.java:50)
	at org.basex.http.rest.RESTCommand.run(RESTCommand.java:40)
	at org.basex.http.rest.RESTPost.run(RESTPost.java:108)
	at org.basex.http.rest.RESTServlet.run(RESTServlet.java:14)
	at org.basex.http.BaseXServlet.service(BaseXServlet.java:58)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:51)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100)
	at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:953)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
	at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1041)
	at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:603)
	at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.doRun(AprEndpoint.java:2430)
	at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.run(AprEndpoint.java:2419)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
	at java.lang.Thread.run(Unknown Source)
 OPTIMIZE ALL 