Weird. I have wished that exact same wish for several times without any issues (As dwarven paladin as well, since one of my favorite RC combinations). Did you use the ring as unidentified? Was the ring equipped? Where did you use it? Anything else you did that might help to reproduce this bug?

Next time you find one, take a back up from your save before you try it. If it keeps crashing you can even share your save game here for other people to try out.

I used the ring in its unidentified form "ordinary ring", i just blessed it and gave it a go without equipping it (I opened the inventory and clicked on the ring, selecting "use it").
Used the first one around D:20 and the second one in Dwarftown.
One was obtained by ring dipping and the other by random loot, if that helps.

This has been fixed a while ago. I can find the ticket ID right now. Works in R66.