Defendant-appellant Universal Security Instruments, Inc. (“USI”) appeals from a March 31, 2006 order of the United States District Court for the Middle District of North Carolina, Docket No. 1:03-CV-00537-NCT, granting the motion of plaintiff-appellee Walter Kidde Portable Equipment, Inc. (“Kidde”) for voluntary dismissal without prejudice of an action Kidde had filed against USI. Although we find that the district court erred as a matter of law when it dismissed USI’s counterclaims over USI’s objection, and when it ruled on a motion for voluntary dismissal without first determining whether it had subject matter jurisdiction, we conclude that, under the circumstances, these errors were harmless. We also conclude that the district court did not abuse its discretion by granting dismissal of Kidde’s claims without prejudice and without conditions. Therefore, we affirm.