Ken,

"runts" are any ethernet packets that are less than 64 bytes.

In a shared Ethernet environment, runt frames are almost always caused by collisions. If the collision rate is high, refer to the problem of excessive collisions.

If runt frames occur when collisions are not high or when in a switched Ethernet environment, then they are the result of underruns or bad software on a network interface card.

Use a protocol analyzer to try to determine the source address of the runt frames.

HTH>