Short answer:
This is a (corner case) problem in the assembler. Until it's fixed, you can do the following:
Append a comment line to WiW2.inc. Any comment will do, as long as the file doesn't end with a number without radix etc.
Longer answer:
Sometimes the assembler needs to peek at the following character(s). This is done by reading character(s) from the file
and then pushing them back to a buffer, which is inspected first when reading the next time.
There is also a "stack" structure for files (real and virtual), where a newly opened file is "pushed" and later "popped"
when EOF is reached. Same story for the main file and included files.
(You can see where this is going, right?)
Peeking at the very end of an included file will pop this file, and the peeked character will be pushed on the file now
at the top of the stack. Normally not a big deal, except when one of the characters is a new-line character which means
this file suddenly has a new "hidden" line, pushing the remaining lines down (in terms of line numbers).
