Hi Hugh,
I tried this code:
------------------------
#chip 10F200, 4
#mem 16
#config  _MCLRE_OFF & _CP_OFF &  _WDT_OFF

dir GPIO b'11111000'
GPIO = 0
-----------------------
When I compile (last update of GCbasic from /newfiles) I get in the assembler code this line:

__CONFIG _MCLRE_OFF&_CP_OFF&_WDT_OFF & _HS_OSC

In the CONFIG line there is the command to use the high speed crystal "_HS_OSC" but the PIC 10F200 has only the internal oscillator so I get an error from gputils:

---------- Capture Output ----------
> "C:\Programmi\GCBASIC_eng\COMPILE.BAT" C:\Programmi\GCBASIC\10F202-test04.txt
Great Cow BASIC (0.9 22/11/2006)

Compiling C:\Programmi\GCBASIC\10F202-test04.txt ...

Program compiled successfully!

Assembling and downloading program ...
compiled.asm:10:Error [113] Symbol not previously defined (_HS_OSC).
> Terminated with exit code 0.

If in my code change the CONFIG line in:
#config  _MCLRE_OFF & _CP_OFF &  _WDT_OFF & _IntRC_OSC
GCBasic doesn't use _HS_OSC

ciao Stefano