JESS: [EXTERNAL] Corrupted Negcnt Error

[Dwight Hare]

During a run I started getting the error

Jess reported an error in routine NodeNot2.tokenMatchesRight
        while executing rule LHS (Node2)
        while executing rule LHS (TECT).
  Message: Corrupted Negcnt (< 0) .

Any idea what this means?

Dwight