steam update causing trouble

[6point2fan]

After the steam update I get an error stating steam has found a problem with my local game files. The error indicates the files will be aquired from steam online. However, clicking "OK" does nothing but cause the error to re-appear. I have the regular boxed retail version.

Any help??
Thanks

 

[Varsity]

steam://validate/220

 

[6point2fan]

thank you!!