amarok2 cannot find any collection plugin

[Kevin Funk]

From the techbase wiki page [1]:
"""
 If you are using the same user to run the KDE4 installed through your system 
package management, you must also export the KDESYCOCA variable (for example 
export KDESYCOCA=$KDEVARTMP/kdesycoca-custom) or change the cache-$hostname 
symlink in this $KDEHOME to a real directory. This also ensures a further 
encapsulation of the development environment (but will cause slowdowns if your 
$HOME is on an NFS share)
"""

Fixed it for me. Had exactly the same issue.

Greets, Kevin

[1]  
http://techbase.kde.org/Getting_Started/Increased_Productivity_in_KDE4_with_Scripts/.bashrc