Also, you seem to use OLE; without needing it anywhere.

You don't want to die MsgBox; that'd take the return value of MsgBox, and use it as a reason to die.

But most importantly, you're making two passes over the data where only one is neccessary.

Instead of @newrecords = (@newrecords,"$name");, just print NEWCUSTLIST $name;, and get rid of your second for loop.

For that matter, instead of reading all of SUBLIST into @pairs, do while ($pair = <SUBLIST>) {

The idea is that less passes is better, and less data in memory at once is better.