Can't Add Long Custom Template File
 

I am able to add and edit custom templates fine, but appear to be having difficulty when adding ones of longer size.

For example, I have a copy of the template saved in notepad at 81KB and when I try adding that as a template I get a white screen. This doesn't appear to be a timeout issue as I get that screen after just a couple seconds.

I tried pruning the template to make sure it was the size that was the symptom and it does appear to be as if I cut it by 25%, for example, it will save fine.

Please help!