GlassFish error redeploy / recharge project

[Thales E. B. Oliveira]

Good morning everyone

I'm still having trouble in glassfish .. When I started the glassfish server and first implemented the project everything works normally. When I try to redeploy or reload the project, start giving error below and no longer causes the application to work until I restart the glassfish server.

[#|2011-09-13T08:48:58.521-0300|SEVERE|glassfish3.1.1|javax.enterprise.system.std.com.sun.enterprise.server.logging|_ThreadID=25;_ThreadName=Thread-2;|java.lang.NullPointerException
	at com.microsoft.sqlserver.jdbc.TDSWriter.writeBytes(IOBuffer.java:2126)
	at com.microsoft.sqlserver.jdbc.TDSWriter.writeBytes(IOBuffer.java:2116)
	at com.microsoft.sqlserver.jdbc.TDSWriter.preparePacket(IOBuffer.java:1934)
	at com.microsoft.sqlserver.jdbc.TDSWriter.startMessage(IOBuffer.java:1987)
	at com.microsoft.sqlserver.jdbc.TDSCommand.startRequest(IOBuffer.java:4943)
	at com.microsoft.sqlserver.jdbc.SQLServerConnection$1ConnectionCommand.doExecute(SQLServerConnection.java:1440)
	at com.microsoft.sqlserver.jdbc.TDSCommand.execute(IOBuffer.java:4575)
	at com.microsoft.sqlserver.jdbc.SQLServerConnection.executeCommand(SQLServerConnection.java:1400)
	at com.microsoft.sqlserver.jdbc.SQLServerConnection.connectionCommand(SQLServerConnection.java:1446)
	at com.microsoft.sqlserver.jdbc.SQLServerConnection.setAutoCommit(SQLServerConnection.java:1594)
	at com.sun.gjc.spi.base.ConnectionHolder.setAutoCommit(ConnectionHolder.java:651)
	at br.com.acifranca.web.filtros.ConnectionFilter.doFilter(ConnectionFilter.java:43)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:256)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:217)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:279)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
	at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:655)
	at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:595)
	at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:98)
	at com.sun.enterprise.web.PESessionLockingStandardPipeline.invoke(PESessionLockingStandardPipeline.java:91)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:162)
	at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:330)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:231)
	at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:174)
	at com.sun.grizzly.http.ProcessorTask.invokeAdapter(ProcessorTask.java:828)
	at com.sun.grizzly.http.ProcessorTask.doProcess(ProcessorTask.java:725)
	at com.sun.grizzly.http.ProcessorTask.process(ProcessorTask.java:1019)
	at com.sun.grizzly.http.DefaultProtocolFilter.execute(DefaultProtocolFilter.java:225)
	at com.sun.grizzly.DefaultProtocolChain.executeProtocolFilter(DefaultProtocolChain.java:137)
	at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:104)
	at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:90)
	at com.sun.grizzly.http.HttpProtocolChain.execute(HttpProtocolChain.java:79)
	at com.sun.grizzly.ProtocolChainContextTask.doCall(ProtocolChainContextTask.java:54)
	at com.sun.grizzly.SelectionKeyContextTask.call(SelectionKeyContextTask.java:59)
	at com.sun.grizzly.ContextTask.run(ContextTask.java:71)
	at com.sun.grizzly.util.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:532)
	at com.sun.grizzly.util.AbstractThreadPool$Worker.run(AbstractThreadPool.java:513)
	at java.lang.Thread.run(Thread.java:662)
|#]

could someone help me?

I thank