Error 22 tells you that there is no writable memory at the address the diagnostic gave you. To make a monitor work on an 8051 you need to overlay XDATA and CODE space so you can "write" to CODE space. This hasn't been done at the address specified with your application. The error message you are receiving is caused by the EZ-USB chip writing to the autovector address located at 0x0045.
This error message can be safely ignored.