Fatal error: capabilities.php on line 428

HELP PLEASE!!! I am so new to wordpress and I’ve been working on my sight for a couple months, I’ve gotten a fatal error before and fixed it but I can’t figure out how to fix this one. This is what my error says.

Fatal error: Cannot call overloaded function for non-object in /home/completerad/public_html/wp-includes/capabilities.php on line 428

I tried to delete that line but it gave a an error that I didn’t have permission anymore. I was able to put that line back in and get back to this error message.

Can someone that can explain how to fix this (in baby terms) please help me???

Thanks
Jessica

If there is any info that is need please let me know. Like I said I am very very new to this and not sure what info I am suppose to put in here.

Thanks