That happened to me too. If you have mobile terminal there's a script you can run to fix that issue.
You have to login as root in order for it to run correctly.
Here it is:
#!/bin/bash
chmod -x /usr/libexec/mobile_installation_proxy
killall -9 mobile_installation_proxy
rm /var/mobile/Library/Caches/com.apple.mobile.installation.plist /var/mobile/Library/Caches/com.apple.LaunchServices-045.csstore
launchctl stop com.apple.mobile.installd
launchctl start com.apple.mobile.installd
while [ ! -f /var/mobile/Library/Caches/com.apple.mobile.installation.plist ];
do
sleep 1
done
while [ ! -f /var/mobile/Library/Caches/com.apple.LaunchServices-045.csstore ];
do
sleep 1
done
sleep 10
chmod +x /usr/libexec/mobile_installation_proxy
sync
reboot;
It worked for me. I hope it helps you out.