Hi. Thanks for the replies.

Alain: I was going to use the syntax later (if thermistor then...), after I had my program working. But as Darrel explained, this would have no effect as the error was coming from the ReEnterPBP.bas.

Darrel: Thanks for the explanation. I forgot to mention that I was using yours routine for the Interupts, sorry... But did not imagine that this could be coming from the ReEnterPBP.bas. It seemed more logical to be a problem of the Assembler or Compiler.

Useful the tip for the error.

Anyway, many thanks to all.

Ioannis