I would assume that somewhere on your harddisk (and especially within $ENV{PATH}), there are DLLs that belonged to the once-Perl-5.18 and for some reason, Perl 5.24 picks them up before picking up its own DLLs. Maybe it's an XML lib, because on line 113 (resp. the statement starting on line 113), you call XMLin, which likely is from XML::Simple and which might use XML::Parser or whatever ...