Hm I see:

 * Successfully mounted /dev/hda3 to /mnt/grml (readonly). [ ok ]
 *   Sorry, could not find file config.tbz on device with label GRMLCFG. [ !! ]
[...]
 * Searching for device(s) labeled with GRMLCFG. [ ok ]
 *   Floppy device detected. Trying to access floppy disk. (Disable this via 
boot option: noautoconfig)
 *   No devices with label GRMLCFG found. [ ok ]

So it seems you are using 'myconfig=/dev/hda1' but you don't have a file named 
config.tbz on that device, right? It's continuing searching for a file system 
with label GRMLCFG later on as well, so if you label that device with GRMLCFG 
and name your configuration file 'config.tbz' it should work for you without 
any further manual intervention, right?

thanks && regards,
-mika-