high structure simulation error with FEKO

hi all.
im simulating afighter with FEKO.
i was import the .dxf fighter model with its mesh into the FEKO, and mount a monopole antena on the structure.
the mesh of the fighter was performed with the 3Dmax , and distinctly has a larg mesh elements.
and the monopole antenna has the small structure (freq = 3GHz), and has small mesh element size.
when i want to run the FEKO, an error occurs " ERROR 240: A triangle is too small or EPSENT is too large".

could anybody help.

thanks

Hi all.
I want to simulate an airplane with FEKO and CST to measure the effect of the airplane body on the radiation pattern of a spiral antenna in 3GHz frequency. I do meshing and all of parameters are valid.
I tried to use MLFMM method in feko to solve, but it doesn't converge. and finally simulation stops after about an hour and passing 100 iteration (defined myself). I tried this in CST too, but it need too much RAM space.
could anybody help me in solving the problem or suggesting any better methods.

Im using a PC with core i5 3.7GHz cpu, and 24GB of RAM.

thank you