acutually it is caused by ulix or ulib cuz if I uninstall it the server works just fine
To give more detail on what Hellfox and MrP have already said, though you may experience the error with ULX installed, it's not directly caused by Ulib or ULX.
ULib enhances Gmod's hooks...we allow for setting a parameter along with the hook that, simplified, sets it a priority, makes it read-only if needed. Can't be overwritten.
It seems you have an addon, that uses hooks, that is probably written in such a way that flips out.
The error you're getting seems to indicate it's written in a way that's not quite right, and are lucky to have it run most times until some other addon tries to use hooks like we do.
