Have you checked the physical interfaces, too? Usually, errors in interfaces are due to bad cables, misconfiguration or bad speed/duplex negotiation or failed NICs. In the swith as well as in the machine/s connected to it.

See if there is a physical int which belongs to that vlan and is having problems. Clear counters, shutdown the int and verify counters in the vlan again many times to see if they increases. Bring the int up again and see what happens. If the counters increase, try to change the cable, check again, if everything keeps the same, change to another port in the switch. If nothig fixes up, maybe the NIC in the host is broken -> change it. If nothing works, well, I don't know what is happening :)