I think these are two separate problems.

I'm not sure what's preventing it finding the the UCSExt.pm module since you say it is in your perl path.

From your code snippets it seems like you have a syntax error on line 18:

@options    $nds             $Ret
[download]

should be

@options,   $nds,            $Ret
[download]

The subsequent "Global symbol requires explicit package name" errors are a follow-on from this. If you fix line 18 the rest will go.