Committed roller rider here .
Koffee really hit on something, you need to relax. Any twitchiness in your movements
gets telescoped up your arms through your white knuckle grip on the bars and
Bobs your uncle your going down.
I did the learn in a doorway trick, but quickly moved out, felt too confining to me, and
got the idea if I did fall there was nowhere to go.
Some hints.
1 DON'T CLIP IN (at least not until you can ride for 5 - 10 minutes without falling)
use sneakers etc. on top of your pedals, that way you can put a foot down (on the
frame) if you have to.
2 I use a step stool to help mount/dismount I can't just swing a leg over and start
pedaling all in one motion.
3) A tall counter (bar height) helps for something to grab onto if you need it. Its
also a great place to put water, coffee, snacks, towels etc.
4) Pedal faster
5) All movement sideways should be done with the hips, not steering with
the bar.
I can drink,eat etc. while on the rollers, can ride for about 2 to 3 minutes no hands
on the rollers but still not quite smooth enough for standing sprints.
Hang in there, it is most definately worth it.
Marty
Here are some additional hints:
http://www.kreitler.com/rolltips.htm