User Carl Nagle ( posted:

Update on this problem noted on the attempt to use an HTML ListBox:

On V2001, we found that a standard HTML ListBox was generating the UNKNOWN
object message followed by the "...DAT exceeds maximum size" message. Our
research found that the GUIOBJ.DAT file in the TMS_SCRIPTS\dat directory
of the Project had about 10 bytes of data in it.

Copying over GUIOBJ_BUILTIN.DAT from the Rational Test directory to the
Project's TMS_Scripts\dat appeared to clear up this particular problem.
At least, we could think of no other action we had performed that could
account for it to start working.