It looks like something is not being cleared internally.
I have this code a few rows earlier...
MACRO MSGLC_INIT(src, trg, vt)
MACRO .btstr(src, trg buf)
If i add the i declaration line like this:
MACRO MSGLC_INIT(src, trg, vt)
MACRO .btstr(src, trg buf)
int i = sizeof(trg) + 1
Now there is this error:
; ASM ERR: va _retval as int == [ebp-0x10]!! Unidentified instruction: va
; AFTER: .pbmain
; LINE: 358
Apparently after this line (around 100 lines ahead):
FUNCTION PBMAIN() AS INT