Is there a chance that the wire pairs on that 200 foot run aren't the proper pairings?

Ethernet cables are designed with certain wire pairs going to certain pins, so that the "twists" in the wire pairs correctly do all of the necessary noise reduction for long cable runs. Someone crimping down an RJ45 plug on either end of such a cable run might not necessarily know about that little detail, and might have done it wrong.

If so, you might have symptoms like those you describe: Depending on what piece of gear you've got hooked up at either end of the cable, it might work fine or it might succumb to noise issues.