The remote Debian host is missing a security-related update.
It was discovered that Perl's Safe module - a module to compile and execute code in restricted compartments - could be bypassed. Please note that this update is known to break Petal, an XML-based templating engine (shipped with Debian 6.0/Squeeze in the package libpetal-perl, see bug #582805 for details). A fix is not yet available. If you use Petal, you might consider to put the previous Perl packages on hold.
Upgrade the perl packages. For the oldstable distribution (lenny), this problem has been fixed in version 5.10.0-19lenny5. For the stable distribution (squeeze), this problem has been fixed in version 5.10.1-17squeeze2.