In MonacoProof v 3.7.1 and MonacoProfiler v4.6.1 some users have unexpected termination of the application when using custom page sizes. This is generally evidenced when the application is receiving data from the instrument.

Two workarounds are available:
Do not use custom page sizes.
Connect the instrument serially instead of USB.

This problem does not occur on Mac OSX. USB connectivity on the DTP41b is not supported under Mac OS9.