Command Line - Jazz Build Engine Null pointer exception

Hi,
Created new build definition with Command Line - Jazz Build Engine in rtc 3.0 with the option "Delete directory before loading" checked and the build was successful.
But for each build request it's taking more time for deleting and loading complete directory structure for the automated build.
So I unchecked the option "Delete directory before loading" and made build request, following errors shown in the build logs.

2011-05-06 10:13:12 running on host: <xxxxxx>
2011-05-06 10:13:12 Should build occur?
2011-05-06 10:13:12 Yes: Always build a user initiated request.
2011-05-06 10:13:13 Invoking pre-build participant "com.ibm.team.build.jazzscm"
2011-05-06 10:13:16 Accepting changes into workspace "<workspace>" ...
2011-05-06 10:13:18 Fetching files to fetch destination "<workpace" ...
java.lang.NullPointerException
at com.ibm.team.filesystem.client.internal.ignore.JazzIgnoreFile.<init>(JazzIgnoreFile.java:106)

Am I missing any configuration?
thanks in advance
Sudhakar