ERROR ID: 243

I am attempting to run topology on line feature class that represent contour line intervals in lakes.

I am getting the following error...

Validate Topology failed.
A failure was detected insited the topology engine overlay precessor. [error id: 243]
The opperation was attempted on an empty geometry


has anyone run into this error before?

any ideas on what i need to try?

the feature exists, and some of the lines MAY overlap, thus the need for topology.

Thanks!