There are several pit falls, one may fall into. There are two milestones for a working amforth: A working command prompt and a successful compilation.
By experience: check your hardware. Check whether you use the serial port that you configured in amforth. Many atmegas have more than one serial port and usually the wrong one is configured.
Next check the baud rate and the cpu frequency. They must match the configured numbers. There are some fuses as well that affect the cpu frequency. Check them too!
Failed to compile¶
If your prompt works, the compile step may fail as well. A definition may not return to the command prompt or any further command fails without any message. There are usually two reasons: The fuses and the fuses.
Amforth requires that the whole NRWW section is used for the bootloader. If the bootloader section is smaller than the maximum (largest) NRWW size, compilation fails.
Another sensitive fuse is the boot reset vector (bootrst). It has to point to address 0, not to the NRWW section. Usually it means to set it to off value.