After a lot of tryouts, i found a (halfway) solution to solve this kind of problem.
The first DataInput work very well, only every run after the first, give me a global radiation and a PET of 9999 (the default of missing value). I dont know exactly why, but i think it can be an issue of my PC. But my work can now go on. So maybe, this tipp will work by you too.
Greetings until the next question