Hi.
The decimal point should be fixed to your country. If it is wrong, then you probably have memory corruption, and the machine should be re-initialised. this will ALWAYS return the decimal point to the correct place. Note- this will lose any sales etc in the machine and start again:
Take one battery out (in printer compartment near paper roll). Set to REG mode. Turn power off at wall for 30 minutes. Turn on at wall. Fit battery back in.
Mark, August 2009