I had this issue and took time to read each forum post with little to no help ever posted as of a fix or cause.
I also watched/read every Perma install guide that I could find and even though they cover many basis they always fell short on covering the way to fix this issue. But I finally found one post that covered the "Debug - MoreHeapSpace".
To break it down for those unsure of what I am talking about: When setting up Permus Maximus you will be setting up the Java patcher. This patcher uses Java but most people have Java 64x. Java 32x is needed for Perkus Maximus. With Mod Manager (After installing Java 32 and Perkus Maximus) you will need to create an executable to the "Debug - MoreHeapSpace 32x".
After attempting to run the Perkus Maximus Java patch and you get a Null Error, you simply run the "Debug - MoreHeapSpace 32x" and let it fully run and patch.
(I know this is an older post about the issue but this is a post that came up the most when I ran into the issue and was looking for a fix. This is why I posted it here)
Edited by DeathDRH, 02 August 2015 - 05:54 AM.