Simple fm tx

recently i have started to work on usrp b200 and to learn gnuradio.
for the beginning i have tried to run two example:

  1. freq hopping
  2. multi freq

when i ran the first one and some errors occurred (attached)
the second (multi freq) was written to an old version ( not uhd driver)

can you help me to run those programs ?

in addition, i have design a simple fm transmitter that is modulated by
10khz tone,
it’s work but not good.
the signal is stable for 1 minute and then many harmonies arise for few
i have tried to fine tune many parameters with no success.
what am i doing wrong?

tank you.