Recently I faced an strange issue related to MOSS. One of my content admin is complaining that he is unable to add any link or page in his site anymore. whenever he is trying to create any page he is getting this error
"trial period for this product has expired"
Our MOSS farm has correct license and we haven't upgraded MOSS from trial version. After thorough analysis and research, I found that there is a bug in MOSS SP2 which reinitializes the license file and turns MOSS normal license to 180 days trial license.
For fixing this issue, you can go to MOSS central admin->operations->Convert license type->Enter product key and add the key again or apply the hotfix mentioned in the below KB article.