I found out that the problem in the code is this

my.move_vec_x = (key_e - key_d)*int(my.a_rennen_p_speed)*time_step; //vorwaerts, rückwärts

now, what is the Lite-C code for int() in C-Script?

My System:
Intel Core 2 Duo CPU P8400 @ 2.26 GHz
4 GB Ram
NVIDIA GeForce 9600M GT
32 Bit Windows Vista
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