The 2612B and Lua 5.0 do support the '...' notation for vararg functions, though it works differently than in Lua 5.1. This is called out in the 5.1 documentation: https://www.lua.org/manual/5.1/manual.html#7.1 and described in the 5.0 docs: https://www.lua.org/manual/5.0/manual.html#2.5.8
I see that state machine code was written for Lua 5.1, so if you're using it directly that would be at least one of the reasons it's not working. Unfortunately I'm only familiar with Lua for TSP, but a dedicated Lua forum might help more if you're trying to adapt 5.1 to 5.0 script.
Always fun adapting other people's code! Let me know if you run into other issues.