Convert .PCB (Protel) to .MAX (Orcad Layout)
The default file extension for Protel PCBs has always been .PCB as far as I know. PROTEL.TCH appears to be a "technology template" file used to set design rules for boards created with Protel (found here)

EDIT

It looks like I misinterpreted what you were doing. As Leon &amp; Kevin have said, Protel files can be saved in binary or ASCII formats. Unfortunately, Protel used the .PCB file extension for both formats. The latest pre-Altium Protel files I have are from Protel 3 which look like this inside :-

PCB FILE 6 VERSION 2.80  for the ASCII format, and 
PCB 3.0 Binary File for the binary format (the first byte is 13 hex).

So it looks like you have an ASCII file, but maybe your import utility expects the file to be in binary format.