Invalid argument in line 259 of cssedit.js

Hi, I installed the CSS module ok and the menu bar appears at the bottom of the page. But when I click on a theme, it doesn't do anything other than that the IE browser displays an error page icon on the bottom left and when I click it, it gives the following error information:

Webpage Script Errors

User Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.1; Trident/4.0; Avant Browser; .NET CLR 1.1.4322; .NET CLR 3.0.04506.30; .NET CLR 3.0.04506.648; .NET CLR 3.5.21022)
Timestamp: Tue, 18 Nov 2008 03:44:07 UTC

Message: Invalid argument.
Line: 259
Char: 3
Code: 0
URI: .../sites/all/modules/cssedit/cssedit.js?3