mod_perl and mod_cgi problems

Hi!

On my Solaris 5.8 machine I'm running apache 1.3.27 with mod_cgi and mod_perl 
1.0. mod_cgi is compiled into apache and mod_perl are loaded in my httpd.conf.

When I'm requesting for any .cgi script (tested with: #!/usr/bin/perl or 
#!/bin/sh) everything works fine, and the scripts compile and return a 200 
message to my browser. But after a request that involves mod_perl - .mpl 
(#!/usr/bin/perl), these cgi scripts crashes with "500: internal server error"

This is the error.log:
libthread panic: cannot create new lwp : dumping core (PID: 9028 LWP 2)
stacktrace:
        ff052030
        0

If I start a truss -p on the apache process (all processes) the request will be 
OK and reply a 200 OK message. After I've turned off all trusses, the 
errormessage is still there.

Then I need to restart apache and all cgi scripts are working fine again.

What can I do to solve this?

Regards, Magnar