It's rather hard to respond to this without knowing whether you have a charger with balance taps or not. It may depend on the specific charger and most of the errors are toward the end of the manual with a tiny explanation of what the error means. I'm guessing that most charger manuals I read are telling you that there's a discrepancy between the set number of cells and what is measured by charger. This can be result of one or more cells being out of voltage spec , connection , wrong balance board, ect. I supose it could also be the battery itself or the charger itself too.

Maybe you can eliminate the charger and check the batts by themselves or eliminate the batts and check out the charger itself?