Name "main::ZNx" used only once: possible typo at ....
Name "main::Znz" used only once: possible typo at ....

##</code><code>##

if ($pdbline =~ /OD2 ASP/ or /NE2 HIS/)

##</code><code>##

if ($pdbline =~ /OD2 ASP/ or $pdbline =~ /NE2 HIS/)