The MoneyWorks GUI app runs in 32-bit mode, so external Helper scripts need to be registered as 32 bit.
The following batch file will register a Helper.wsc in your custom plugins on 64-bit Windows 7.
set REGTOOL="C:\Windows\SYSWOW64\REGSVR32.EXE"
set TARGET="C:\Users\YOURUSERNAME\Documents\MoneyWorks Custom Plug-Ins\Scripts\Helper.wsc"
set ENGINE="C:\Windows\SYSWOW64\scrobj.dll"
%REGTOOL% /i:%TARGET% %ENGINE%
You'll need to "Run as Administrator"