While looking at his perpetual calendar, Dilbert asks Dogbert to guess what day of the week January 1, 2222 will be. When Dogbert replies "Twos-day" (i.e. Tuesday) Dilbert replies in the negative. January 1, 2222 will, in fact, be a Tuesday.
Dilbert states that "a big round number is coming up" and the episode is entitled Y2K, suggesting the new year's eve would be followed by January 1st, 2000. The real start of the third millennium and the 21st century starts on January 1st, 2001 and NOT 2000 as suggested in popular culture. As an engineer he should know that.
The program for the old computer is said to be written in COBOL, but what's shown on the screen is in C++, a language developed much later.
When we see the computer screen reflected in Wally's glasses, the program is still readable left-to-right, instead of reversed.