penaly tax for late 401K deposits

[Guest ANITAO]

I have an employer who missed including a small payroll in his monthly 401k deposit for Jan of 1999. The error wasn't discovered until the year end reconciliation was being done in Jan of 2000. The employer immediately deposited the contributions to the trust. They will submit a 5330 for 1999 to pay the excise tax. Are they required to file a 5330 for the 2000 year and again pay an excise tax because the amount remained outstanding as of 1/1/2000? Also, should the employer contribute lost earnings and how should the earnigs be computed?