main'foo indicates you're using a VERY old version of perl. A single quote used to be the package delimiter, but now it's ::.
Those old perls are no longer supported in any way, so your best bet is to install a newer perl.

From perlmod:

The old package delimiter was a single quote, but double colon is now the preferred delimiter, in part because it's more readable to humans, and in part because it's more readable to emacs macros. It also makes C++ programmers feel like they know what's going on--as opposed to using the single quote as separator, which was there to make Ada programmers feel like they knew what's going on. Because the old-fashioned syntax is still supported for backwards compatibility, if you try to use a string like "This is $owner's house", you'll be accessing $owner::s; that is, the $s variable in package "owner", which is probably not what you meant. Use braces to disambiguate, as in "This is ${owner}'s house".

2;0 juerd@ouranos:~$ perl -e'undef christmas'
Segmentation fault
2;139 juerd@ouranos:~$
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