Maybe Newbie: PHP-scripts in sub-directories

Hi NG, I'm very sorry to bother you, but I've wasted a week solving my problem and didn't find any solution in the net. On my dedicated server preinstalled with Linux Suse 9.0, Apache 2.0.48, PHP 4.3.3 in want to use php in subdirectories. In the main document root of apache my test.php (consisting of the simple phpinfo()-function) works fine. But if I copy the file in any subdirectory I get a error message like 'Premature end of script headers...'. Please tell me, what might be the reason for that? Must there be a right configurated '.htaccess'-file? What must be inserted? Has it to do with rights (I gave the subdir 777-rights recursively to be sure)? Thanks for your reply. Oliver.