[Luk_Ass]

I am not sure but I think HTTP(playerid, HTTP_POST, "myweb.cz/test.php", "filename=dest.txt&input=1. line", ""); and HTTP(playerid, HTTP_POST, "myweb.cz/test.php?filename=dest.txt&input=1. line", "", ""); is the same.
However my method works.