I spent about an hour troubleshooting why a stupid popup window wouldn't work in IE. I tried everything - I renamed the window. I added "void" to the var in the js function calling it. I moved the script inline, and then to a separate script page. I tried everythng, but would always get the same nonsense error:

Error: Invalid argument
Line: 37
Char: 2
Code:0

on file: scripts.js. When I added it inline, it changed to:

Error: Invalid argument
Line: 37
Char: 2
Code:0

file: index.php

The problem? Apparently, IE cannot process a window name if it has a space in it. Ridiculous!