Originally Posted by atucker22
Because everyone has 120 dollars to spend on a DS to use once.
But if you go to a WiFi hotspot, like a cafe, you can search on WiFi and probably find a riolu up for trade
I believe this exemplifies one of the reasons why we have friends, so we can, you know, get help from them if we need it...Resources, man.
Anyway, this sounds like a weird glitch, especially since it only happens at that time and place for that certain event. My copy of Ruby used to freeze up, but it would just happen whenever, and for no apparent reason. From my personal perspective, freeze glitches are never any good, because whenever they happen to me, they're very incessant and generally screw up the game I'm playing (I've only had this happen with about 3 games, though).
Since you've beaten the Elite 4, though, you can probably just perform a search for Riolu on the GTS and see what happens. Riolu is generally rather valuable because of Lucario's competitive viability, but as such, there's a lot of them, and thus there's bound to be someone who's offering one for some rudimentary Pokemon you can go catch in about a minute's time.