I just re-installed my windows and just setup fs9 and all PMDG 737 modells. 

I really need your help, I just dont know what's wrong here.

 

I'm trying to setup my FMC pre-flight ESSA-ESPA wich is  just 373.6 nm and my fuel calculation tells me

i just need about 11.000 kg and even with 100% fuel my FMC tells me I will dont have enough fuel, whats wrong??

 

My first reaction is you have not completed the set-up of the FMC. Check the PROG page and post that please.

 

Have you checked the legs page to see that you have no disconinuities or a rogue waypoint in there?

 

As an aside, you are not losding the taknks correctly. The 737 procedure is fill the wing tanks, then put at least 500 kg in the centre. centre tank is used first, before any wing tanks.

I have sometimes this problems, just check all the waypoints, some times a waypoint was incorrect or misplaced by the FMC, what i do to check that is to place the nav display on plan , fully zoomed out and the in the FMC legs page i click on step to check for a logic flight plan, as i plan using sky-vector, i know how to route should look. The problem is that, if the fmc tells there is not enough fuel, the AP wont engage. 

Waypoint 1: Not far from Stockholm, Waypoint 2, not far from waypoint 1, Waypoint 3 in Brazil 3500nm away, Waypoint 4 back in Sweden 3600nm from waypoint 3... = no 737 can ever get there.

Check out where those waypoints are. Is one a few thousand nm away? there's your culprit.