"M" market code is "Other Areas" in Kenwood land.
L = Scandinavia
K = USA
P = Canada
Y = Far East
T = England
E = Europe
C = China
X = Australia
KPG-137D is the correct software for the TK-x000 line of radios.
However, the TK-2000/3000 were never sold in the USA, as far as I can tell. That jives with the "M" market code. The trick with Kenwood software is that the KPG software has to be activated with the correct market code serial number to match the radio. That way the software knows what parameters the radio is requires to run under to be legal in the country in which it is used. If you "found" the software under some internet rock somewhere and activated it with some random serial number found under some internet rock somewhere, then it's likely the software key doesn't match the market code of the radio.
The solution to this is to redo your software installation and make sure you find an activation serial number that is for the M market code. That'll serial number should look something like: 137M4#######XXXX
And, I agree with above. If you bought this radio off e-Bay, see if you can get your money back. Finding the correct software serial number might be easy, might be impossible. Also, the radio likely does not have FCC type certification for legal use on anything other than the amateur radio bands.
