Hi, I seem to be not the only one that has problems with Semaphores in the apache-mod_perl context: We run a redhat6.2 server and have installed a apache_1.3.12 with mod_perl_1.24 and mod_php4.01pl2 (linked statically, since DSOs do not work as posted in this group) We want to use Apache::Session::DBI to TIE a %session Hash for each user session to a database (sessiondb/sessions). After installing all necessary perl modules (why are they not included in the CPAN Bundle::Apache?) I call PerlModule Apache::DBI in the httpd.conf file and after this PerlRequire apache_handler.pl which initializes the database access and does the cookie handling, that writes session info to the %session hash, tied to the DB. On startup, everything is fine, after the call to the first Mason component, I get the %!*&!%/$§ message :-( Permission denied at /usr/lib/perl5/site_perl/5.005/Apache/Session/SysVSemaphoreLocker.pm line 63. Apache::Session::SysVSemaphoreLocker::acquire_write_lock('Apache::Session::S ysVSemaphoreLocker=HASH(0x83018fc)', 'Apache::Session::DBI=HASH(0x8301908)') called at /usr/lib/perl5/site_perl/5.005/Apache/Session.pm line 560 Apache::Session::acquire_write_lock('Apache::Session::DBI=HASH(0x8301908)') called at /usr/lib/perl5/site_perl/5.005/Apache/Session.pm line 478 Apache::Session::save('Apache::Session::DBI=HASH(0x8301908)') called at /usr/lib/perl5/site_perl/5.005/Apache/Session.pm line 375 Apache::Session::TIEHASH('Apache::Session::DBI', undef, 'HASH(0x8301878)') called at /etc/httpd/Mason/apache_handler.pl line 70 HTML::Mason::handler('Apache=SCALAR(0x830186c)') called at /dev/null line 0 eval {...} called at /dev/null line 0 I am sure, you have got this problem earlier (I am spending now the second day on it &%§$*%% ggrr :-((( Help very much appreciated, thanks Markus