Quite a lot people including myself have this issue with RMAH for the last 7 days or so.
I cannot place an auction with funds going to paypal. Other people have reported being unable to use paypal at all.
This is on the US RMAH, and does not seem to affect people in US, just outside. I suspect it's some problem between RMAH and paypal.

I did wonder why gold price has stopped dropping and in fact climbed a little. Maybe all those gold farmers unable to sell ATM ? Expect gold price to tank when this gets fixed !
I also wondered why my stuff is selling pretty slowly on RMAH compared to GAH for the last week.

http://us.battle.net/d3/en/forum/top...4010631?page=2
http://eu.battle.net/d3/en/forum/top...4175282?page=2

[edit] Looks like this has just been fixed a few hours ago !
http://us.battle.net/d3/en/forum/top...890005?page=16