Pro Site - Error 500 in front page since 3.0.3

Hi, i have a strange problem on one of my network site.
Since i have updated to pro site 3.0.3 i have a 500 error on front page (only the front page) of all my network sub site, but not on site using domain mapping.
If i de-activate pro site, i can access front page again.
Someone else have this problem ? Where can this come from ?