Error when I switch to server mode

I was previously using embedded mode without any problem.  Today I tried to switch to server mode, and after connecting and doing some db operations I got this:

[ObjectDB 2.0.3_04] Unexpected exception (Error 990)

Generated by Java HotSpot(TM) Client VM 1.6.0_21 (on Windows 7 6.1).
Please report this error to ObjectDB support ([email protected]).
com.objectdb.o.InternalException: java.lang.NullPointerException: null

java.lang.NullPointerException
 at com.objectdb.o.MST.aS(MST.java:816)
 at com.objectdb.o.MST.aR(MST.java:786)
 at com.objectdb.o.MST.UO(MST.java:420)
 at com.objectdb.o.WRA.UO(WRA.java:243)
 at com.objectdb.o.WRA.UO(WRA.java:243)
 at com.objectdb.o.WSN.UO(WSN.java:294)
 at com.objectdb.o.STC.o(STC.java:359)
 at com.objectdb.o.SHN.ab(SHN.java:393)
 at com.objectdb.o.SHN.I(SHN.java:132)
 at com.objectdb.o.HND.run(HND.java:119)
 at java.lang.Thread.run(Unknown Source)

I'm just doing a simple insert.

The stacktrace indicates a problem in retrieving an object in a client-server mode. Somehow the type of the object is unknown on the server side - but I couldn't reproduce the exception, since normally the client registers types with the server before they are needed.

Please check the new build (2.0.4_03) that might fix this issue (by considering unknown classes on the server as classes with no instances, assuming that this is the problem).

However, if you could post a simple test case that demonstrates the problem it might help.