The version came with the Softec PK-HCS12C32 Starter Kit.
The Disk says 3.0 for 68HC(S)12
The "about" file says:
IDE version 5.51272
for Motorola HC12 3.1, build 4047
You may be correct in your diagnosis.
I made another project, and copied just a portion of the old code in main.asm, and it's working.
My HC11 code takes up 1100 lines, and 1600 bytes of code.
To start porting, I pasted all the HC11 code into the example framework, then commented it all out.
Then I started adding HC12 code a line at a time, leaving the HC11 code in place, to work from.
Don't know how many lines total before it gave the error. I think I had about two hundred HC12 lines before it bombed.
I remember downloading and installing the license file last year. The file is pretty big, and has three sections.
Section one talks about the demo version
Section two talks about the pro version
HC12 professional edition V3.0
IDE unlimited, advanced beans and bean wizard
Section three talks about the special version
HC12 Special Edition for V3.x
IDE: learning edition max 32 files
unlimited assembly/Hex/S19, C code up to 12k
Processor expert basic beans