Unfortunately strict is not used in any of these scripts.
When I began writing a test.pl script using strict it became obvious that the scripts would have plenty of warnings (it would be nice to avoid having to write in a compatible way with this system but I'm afraid thats a can't do). I have been advised not to use strict by one of the original developers of the code. However I am fortunate enough to also be working on a part of the system which can be relatively separate from the rest, but I am hoping to extract what is reusable from the bulk of the system and write those into packages (a project which has been started).
The existing system uses alot of global values which to an outsider like myself are ambiguous at first until I follow through their use (makes for plenty of reading). Alot of these globals refer to local directory structures, database settings and a global array stores the most recent results from database queries. These are not passed between subroutines but are frequently assumed to be defined. Similarly references to external subroutines do not follow the $object->dosomething() layout but imply that the external subroutines have been imported and are able to be called similarly as if they were included in the body of the calling script. This makes the collection very tangled indeed (grep has become a close friend).
I will have a read through the links you've supplied.