If a CTR or SAR is filed incorrectly or not at all how long is a finanical institution how liable?

Incorrectly: that depends on how incorrectly we're talking.

Not at all: Until a regulator catches it. I personally don't know of a statute of limitations on that one.

You may not be on the right web site to get an informed answer to this question. If the failure was due to negligence, the concept of a statute of limitations does not apply. If the failure was "knowing" or "willful," you should seek the opinion of a criminal attorney, a good one.