Rolled over IRA from one institution to another, but the former labeled it as premature withdrawal. Advice?

a credit union acct is not an IRA - it's only a rollover if the 401k administrator directly transfers it to the new ira administrator - if they send you a check and then you put the money in that's different. I guess if you can prove you got the money from the 401k to an actual IRA in less than 60 days you should be okay - copies of checks and statements will help