Like most who are using this service, I am new to using 8052-BASIC.

I am using the famous "The Microcontroller Idea Book" and wired the first circuit (fig 3-1). I can power it up and after hitting the space bar I get the *MCS-51(tm) BASIC V1.1* READY prompt and all the commands like print xtal and print MTOP(32K) work but when I try to program I get the "Error: invalid line number" message.

How can I fix this?