And what does the script look like? Right now, I can only guess that somewhere there's a line like this:
[tt]$COMD $PARAM[/tt]
and COMD is an unknown shell variable; the variable PARAM is set to "A300", which builds the command line
[tt] A300[/tt]
which the shell complains about. It treats A300 as a command which it can't find.
HTH,
p5wizard