XF 1.1 Image uploads and Mod_security

Hey Guys

I'm trying to solve the problem with uploading multiple images.

I am currently using the non-flash image uploader (flash uploader didn't work properly on PC/Mac so I disabled it)

I understand the Flash uploader might solve the problem but I have to solve the initial problem that caused me to turn it off.

So I found this thread:

However I have no idea where the mod_security settings are located - can anyone help point me in the right direction please.