OMS Error when using Matrix Tool

Version: 
1.4.6R
Operating System: 
Windows XP Pro
Tool: 
Matrix Tool

I am getting an error message when using the Matrix Tool which says "Matrix Tool: OMS Error: An outgoing call cannot be made since the application is dispatching an input-synchronous call". I then have to use the Windows Task Manager to shut down the Matrix Tool.

The error occurs when using the Matrix tool. I simply open the tool to edit an existing matrix and then do nothing, simply wait for a few seconds and the error pops up.