every once in a while FF will insert a local chrome address into my address field - this is the error:

Firefox can't find the file at jar:file:///C:/Program Files/Mozilla Firefox/chrome/en-US.jar!/locale/browser-region/region.propertiesus.ard.yahoo.com.

I bolded the inserted text.

Does anyone know why that happens? and how to stop it?

It could easily be an infection causing that. What protective software do you have and what does it say when you do a full scan?

It's looking for the jar file that installs the chrome theme (I think).
Reinstall this theme, or another and see if that helps.

ya man u need to upgradde ur browser

It's looking for the jar file that installs the chrome theme (I think).
Reinstall this theme, or another and see if that helps.

I went into about:config and found something that might have been the problem. Going in there gets scary but....

Thanks for the pointer

ya man u need to upgradde ur browser

You need to get a clue.

ya man u need to upgradde ur browser

Welcome to the site....

Please dont blindly offer advice w/o knowing whats going on :)