The embedded RLink (ST72F651 device) measures the voltage of the target VCC. It does not make sense in the specific case of the STM32 Primer (because both the STM32 and the ST72651 share the same power).
However, the RLink recognizes that the voltage is not correct...
Seems to be a hardware problem. Possible causes:
1. The ADC of the ST72F651 does not work (never seen before on RLink)
2. There is a connection problem (probable). For sure, it has worked (because the STM32 Primer you received had beed tested and it was working properly). If you look at the schematic, you will see that the problem could be either on the pin 54 of the ST72651, or with the R17/R18 resistances. If you are equipped, you can try to check these points. If not, I suggest that you ask your distributor for a replacement.