HTA VBS errors in WinPE are blank! Why?

Hi folks,

I have an HTA which has some VBS.

Whenever I get a script error, a blank dialog box appears. Blue top bar, with an X, no text, and a large white box, no text or buttons.

The WinPE version we are using, if I type VER, is 6.1.7600.

Any ideas why this happens... and how to fix it? Would be really handy to know what line my script errors occur on. At the moment I have to put msgbox's in to try to catch where the error lies.

Thanks.