I have been troubleshooting this error for days, and I finally figured out the cause of the Invalid Submission Error Message.

The cause is good old Nortons Antivirus 2006. It has a webprotect function built in that you need to disable.

Here is what needs to be disabled to eliminate that stupid annoying Invalid Submission Error.

Go to the Web Browsing Center of your Nortons Anti Virus Program. Click AUTO PROTECT and then SELECT Configure Auto Protect. Next click Internet Worm Protection >>> Configure Exclusions and then uncheck: MySQL StackOverflow THEN click OKAY.

I don't know how safe it is not to be protected, but I figure I have gone years without it with no problems and I really hate that stupid invalid submission error.

If this helps anyone, please let me know. It was driving me crazy.