Read/Writ access to OSBoot

Dear readers

I need to install some perl modules for apache.
Unfortunately I get an error saying that there is only read-only access to the system.
Can I change this and if so how and where?
Below is the output I get from the command “perl -MCPAN -eshell”

bash-2.05b# perl -MCPAN -eshell
Cannot open >/System/Library/Perl/5.8.6/CPAN/Config.pm at /System/Library/Perl/5.8.6/CPAN.pm line 1219
CPAN::Config::_configpmtest(’/System/Library/Perl/5.8.6/CPAN’, ‘/System/Library/Perl/5.8.6/CPAN/Config.pm’) called at /System/Library/Perl/5.8.6/CPAN.pm line 1253
CPAN::Config::load(‘CPAN::Config’) called at /System/Library/Perl/5.8.6/CPAN.pm line 92
CPAN::shell() called at -e line 1

Thank you in advance for anyones help and tips.
Kind regards
Thomas Thaler