Compiler gives strange error message (solved)

[baltasarq]

After doing some more changes to my project, zxbc started to complain about "Can't convert non-numeric value to string at compile time", check it out:

Code:

reveni.bas:46: error: Can't convert non-numeric value to string at compile time
reveni.bas:44: error: Can't convert non-numeric value to string at compile time

The second error is signaling a line that... is empty! The first error refers to the following source:

Code:

clrscr()

I think this means that the compiler gets somehow confused about something. I'm attaching the project.
Thanks,
-- Baltasar