Line 108 of HTML::TreeBuilder is a call to HTML::TreeBuilder::parse, which (according to lines 1967–8 of the source code) is inherited from HTML::Parser. Parts of that module — including the parse method — are implemented in C, which is compiled for your local machine when you install the module.
So, it seems there are two possibilities:
The call to get is failing, as suggested by Anonymous Monk, below. So, the first thing to do is to print out the variable $contents immediately following the call to get but before the call to new_from_content, to verify that get is working correctly.
If it is, then check the installation of HTML::Parser on the machine where the code is failing. Perhaps try re-installing this module.
Hope that helps,