Reverse gear failures in the manual transmission models are common.Google+
Car Problem Reports
Volkswagen Beetle Reverse Gear Failures and Noise in Manual Transmission Models are Common
Volkswagen Beetle Problem
Average Mileage: 126,000 mi (52,000 mi - 200,000 mi)
Mine did that when I first got her in 2010. Took her to Autobahn in Memphis, TN. They fixed it, but I can't remember what the heck they did. No problems since, but VW manuals are "slippery." So WARNING: Do NOT let anybody who's not a VW person drive your VW manual!!
Visitor, 1998 Volkswagen Beetle, 52,000 mi
I had to rebuild entire transmission at 52, 00 miles!!! All gears went progressively, on a 2005 Bug with minimal use. 52 k miles at 2013. I was told that the valve body was defective... but I have not seen any recalls... cost me a fortune!!! Wouldn't buy another VW, after being VW owner since, 1976.