PSCS5 Error 22: Window does not have a constructor.

I am having a problem running scripts in PS CS5.

When I try to run the load files into stack script, which works fine on CS5 on my laptop running Windows 7 64bit.n (i7 Processor, 4gb Ram)

I am running the same operating system on my main pc (i7 Processor 6gb ram), and am using the 32bit version of PSCS5.

For some reason however I get the following error when trying to run the load files into stack script.

Error 22: Window does not have a constructor.

Line.388

->         var w = new Window(res);

I have tried trashing my preferences and reinstalling photoshop but neither has worked.

Any suggestions on how to fix would be welcome.

Regards

Robyn