The Elvira chips aren't really errors in the sense they were all made the same way for that particular year:

2000 was missing a $5 on one side, the limit was 999 and 32 was in 2 places on the roulette wheel.
2002 had $5 on both sides, the limit was changed to 666 and the 32 near the top was changed to 23
2003 switched the location of 23 and 32 on the roulette wheel.

Supposedly there is an Elvira out there that has the same picture on both sides of the chip. I've never seen it but maybe someone else has.