Do you have confixx including suPHP installed ?
that won't allow .htacess files and will print out error 500 everytime there
is one in the directory
you need to set that up in confixx -> Admin -> Settings -> http sepcials -> change user -> webX -> advance ....
there is a textfild to write the content of .htacess and save
wait for counterscript.pl to run or start it manually
done.