IMac Upload error

I have a IMac Core 2 Duo 3.06ghz. It runs programs such as Final Cut Pro. A few months after I got it, I started having this file upload error, where whenever I upload a photo or doc to my Yahoo Mail or Youtube or any other site, it says file upload error on each site or another canned message. However, If I try and upload something on Windows Live Mail or Facebook, I have no problems. I'm assuming because this is flash. Any ideas?

Is all your system software up to date? Sometimes a update is what fixes this type of problem. Also check to see if your Flash software is up to date.

Also what browser are you using? Safari, Firefox, etc.?

Its all up to date. I'm using Safari. Same error in Google Chrome.
I also found some unprepared disk permissions just a few mins ago
It says in 12 pages a lot of bad permissions. They all have to do with my Airport.
I don't want to repair them though because I'm using Little Snitch on some of my files for security. I'm afraid it will mess with some of these settings.

BTW, I just went into software update. It can't check updates because of a "network problem". Any ideas?

I just saw this thread. Will these tips disable my Little Snitch? Apple - Support - Discussions - Can't download software updates or ...

Especially the user preferences one!

Any ideas?