turn on sanitize feed in your settings and see if that doesn't help.

Now for my problem, I have a young lady who has upgraded to 1.5.1 and has not been able to output a feed since. It works until it gets to product 3891 and then does this:

WARNING: An Error occurred, please refresh the page and try again.

I've tried resetting the timeout with no change. Set the max products and success at only 1000 products:

Google Merchant Center File Complete In 27.964173 Seconds 999 of 1000 Records which takes it to product id 3361. I've never run into this before - I used to be the one who answered the questions on this! Anybody got ideas? Must be a server limitation I assume but not sure how to overcome it or what to look for.