Unspecified Error in IE6

So I've got RC1 working fine on my server but RC2 is giving me an error:

Line: 19
Char: 64
Error: Unspecified Error
Code: 0
URL http://ezsite.ads.duke.edu/admin/FCK20R ... lbar=Basic

When I turn on script debugging, with the Microsoft Script Debugger installed (a very useful tool, since IE's default error messages suck compared to gecko)... the debugger says the error is here:

return documentElement.createStyleSheet(cssFileUrl);

It's in code_ie_1.js

This error doesn't occur in Firefox.

help!