nm-applet cannot connect to GSM/HSPA network more than one time per system start

If I connect my USB modem to my Eee PC 1005 HA, Ubuntu NBR automatically establishes a connection to the GSM/EDGE/UMTS/HSPA network and I can use the Internet. If I select disconnect, plug off the modem, and then plug it in again, I see a circle turning around, but it never stops and I get no connection. I have to reboot the system in order to get it work again.

ProblemType: Bug
Architecture: i386
CRDA: Error: [Errno 2] No such file or directory
Date: Sat Mar 20 20:08:53 2010
DistroRelease: Ubuntu 9.10
IfupdownConfig:
 auto lo
 iface lo inet loopback
InstallationMedia: Ubuntu-Netbook-Remix 9.10 "Karmic Koala" - Release i386 (20091028.4)
IpRoute:
 192.168.1.0/24 dev wlan0 proto kernel scope link src 192.168.1.106 metric 2
 169.254.0.0/16 dev wlan0 scope link metric 1000
 default via 192.168.1.1 dev wlan0 proto static
Package: network-manager-gnome 0.8~a~git.20091014t134532.4033e62-0ubuntu1
ProcEnviron:
 LANG=de_AT.UTF-8
 SHELL=/bin/bash
ProcVersionSignature: Ubuntu 2.6.31-20.58-generic
SourcePackage: network-manager-applet
Tags: ubuntu-unr
Uname: Linux 2.6.31-20-generic i686