It's a distinct possibility...
Do you have any other PS/2 keyboards you can test with it?
Even if you do, and it tests out fine, it could be simply that your Gateway 2000 keyboard isn't fully compatible with that adapter (certain keyboards draw more power than the adapter can provide, which causes the errors). This happens more often on these types of adapters with the two PS/2s (I remember mine couldn't run both my Model M and my mouse simultaneously).