What's wrong with this? (*solved*)

[na_th_an]

Maybe I'm just being thick:

Code:

Sub Fastcall tdPutChar (c as uByte)
    Asm
        rst 16
    End Asm
End Sub

Sub tdPrint (cad As String)
    Dim i As uByte
    For i = 1 To Len (cad)
        tdPutChar (cad (i))
    Next i
End Sub

Compiler output:

Code:

H:\Dev\Speccy\mt64x32lib\zxbasic>c:\zxb\zxb textdongle.bas
Traceback (most recent call last):
  File "zxb.py", line 312, in <module>
  File "zxb.py", line 241, in main
  File "ply\yacc.pyc", line 263, in parse
  File "ply\yacc.pyc", line 710, in parseopt
  File "zxbparser.pyc", line 1744, in p_statement_call
  File "zxbparser.pyc", line 1137, in make_proc_call
  File "zxbparser.pyc", line 744, in check_call_arguments
  File "zxbparser.pyc", line 432, in typecast
  File "zxbparser.pyc", line 1019, in make_typecast
  File "obj\errmsg.pyc", line 22, in syntax_error
TypeError: %d format: a number is required, not NoneType