This happened to me ALL the time in FM10...it was so frustrating. After progressing from my youth team to the reserves and doing well there, I would decide he's ready to loan out. On the player's personal status it would say "hoping to get loaned out for first-team experience" or something like that. Yet they would always say they had no intention of going on loan to my feeder clubs. So I got a feeder club in the top league in Romania (I was a Portugese team, so not too much difference), and they STILL wouldn't go there. I would offer them to clubs and usually their wouldn't be any takers.
One player had a lot of potential and was too good for my reserves but there was no room for him at all in my first team. I couldn't loan him out the first year for those reasons, and the next year, after offering to clubs, I got a few offers from very good teams that he wouldn't play at (top teams in Ligue 1, Bundesliga, mid tier English team, and i think Inter as well). They were loan to buy but I got rid of the future fee clause and they were willing to do it. I had no choice but to loan him out, and he didn't play a single minute.
It's something they really need to fix, not sure if they have or not in FM11. The only thing you can do is add another manager and make a loan offer (you can go into FMRTE to switch the new guy with the old manager afterwards). I've had some success with this, though sometimes they still won't accept. Going in to FMRTE and making the other team and coach as the player's favorites helps but won't always.
Probably one of my least favorite things about the game.