Thank you. I removed transparency and overlay alternatively but it didn't show up.
For collision I'm using the standard hulls fat/narrow.
Another error just showed up, and I'm not quite sure if I even changed anything. I must have, otherwise it makes no sense. In any case, now the player is shooting himself...
Edit: By the way, does someone have an explanation why c_trace and trace behave differently?#
2nd Edit: Just found out what the use_aabb mode really is

That part is working now. Just the crosshair is still not there.
3rd Edit:
I managed to solve all the problems on my own. They were all related to the new syntax. Anyways, thanks again!