Actually the full message you get with that error should give a reasonable clue. It is likely to be of the form:
ERROR (CAPGEN-41414): -dsub layer 'someLayer' not found in lvsfile.
The root cause is that the lvsfile (which is generated from the
extract.rul in the techgen compilation step) has got out of sync with
the extract.rul file since the last time the techgen compilation was done.
At least that's what I think the problem is, from the limited information you gave...