[Motorola] error#56

[Jeff]

I have several Radius low band 6 channel radios that I gave to a friend of mine to program.  2 out of 5 radios of the radios could not be read.  After the percentage bar, that comes up durring reading has hit 100%, the screen comes up with an error message that says, "ERROR #56 HAS OCCURRED   RADIO CODE PLUG ERROR".   What is wrong?  Can't read from or write to either of the 2 radios that the message comes up on.  However the 2 radios that have this problem both have the "good radio beep" and work just fine except for reading from, or writing to.  All 5 radios are model number D51LRA9734BK. Could it be that newer software was used to program the 2 radios than what was used to read them?  Are they just stuck on the freqs that are in them now?  Any info will help.  Thanks, Jeff