Momentics IDE debug problems

The momentics IDE debug function used to work well on my computer, but today i get the following errors when I try to use it:

An internal error occurred during: “System Information Refresh - windup”.
java.lang.NoClassDefFoundError: com/qnx/tools/ide/target/core/ThreadHelper
COM.newmonics.PercClassLoader.RuntimePercLoader.loadPercClass(Unknown Source)
COM.newmonics.verifier.RuntimeClassReader.resolveConstantPoolEntry(Unknown Source)
COM.newmonics.verifier.RuntimeClassReader.resolveConstantPoolEntry(Unknown Source)
COM.newmonics.verifier.RuntimeClassReader.translateBytecodes0(Native Method)
COM.newmonics.verifier.RuntimeClassReader.translateBytecodes(Unknown Source)
COM.newmonics.PercClassLoader.DynamicPercLinker.prepareOneRuntimeMethod(Unknown Source)
COM.newmonics.PercClassLoader.DynamicPercLinker.prepareOneMethod(Unknown Source)
com.qnx.tools.ide.target.internal.core.RefeshManager$RefreshJob.run(Unknown Source)
org.eclipse.core.internal.jobs.Worker.run(Unknown Source)

These errors occur before the debug window shows up. It used to work fine and I never change everything before. Does anybody know how to fix it? It’s so weird.

Thanks!
Yicheng

Looks like the QNX_HOST environment variable isn’t set…

Here is my QNX_HOST setting:

#echo $QNX_HOST
/usr/qnx630/host/qnx6/x86

is this wrong?