There is no more space in RAM for programs or variables. Delete unused programs and variables. If the memory is fragmented because of numerous deletions it can be consolidated by issuing the commands STORE save_all ZERO and LOAD save_all. This writes the memory contents to the disk and reads them back into memory. Note however that this procedure does not retain any variables that are not referenced by any program in memory nor does it retain the values of variables that are defined to be AUTO or LOCAL.