Thanks for quick replies!
vmroyale
Host: 5.0.0 build 1117897
vCenter: 5.0.0 build 623373
weinstein5
I didn't have some reservations what I could see but I did have some limit's. I took them away but no change.
a.p.
Okay! That's probably the reason! But I guess I don't have update 2 on the hosts as well..? update is 5.0.2 right?
How would you recommend me to upgrade? First vCenter and then the hosts?
Do I need to uninstall vCenter first or will it recongnize that I already have one and then upgrade. I really don't want to loose all my configs... 
thanks!