The file indexing does not work reliably. Often the error message [1] is shown. If the file indexing work, .xsession-errors is full with this kind of messages shown below. I also posted to kde forums [2], but now I think this is worth a bug report.

------.xsession-errors---------------
"/usr/bin/nepomukservicestub(1089)" Soprano: "SQLExecDirect failed on 
query 'sparql select ?r where { ?r 
<http://www.semanticdesktop.org/ontologies/2007/01/19/nie#url> 
<file:///home/killmann/Seizure%20Prediction/Features&Measures/Measures/AR-Estimation/AR-timedependent/outputThunderbold/PERT-48_101029-09-00-01_n1_p20_N5000/recEm.bin> 
. } limit 1' (iODBC Error: [OpenLink][Virtuoso iODBC Driver]CL064: Lost 
connection to server)"
[/usr/bin/nepomukservicestub] "/usr/bin/nepomukservicestub(1089)" 
Soprano: "SQLExecDirect failed on query 'sparql select ?r where { ?r 
<http://www.semanticdesktop.org/ontologies/2007/01/19/nie#url> 
<file:///home/killmann/Seizure%20Prediction/Features&Measures/Measures/AR-Estimation/AR-timedependent/outputThunderbold/PERT-48_101029-09-00-01_n1_p20_N5000/recEm.bin> 
. } limit 1' (iODBC Error: [OpenLink][Virtuoso iODBC Driver]CL064: Lost 
connection to server)"
"/usr/bin/nepomukservicestub(1089)" Soprano: "Invalid iterator."
------.xsession-errors---------------



[1] http://cloud.brain-frog.de/apps/files_sharing/get.php?token=f071cdc66c916da615a1e4dc0f6946c87b27aeed
[2] http://forum.kde.org/viewtopic.php?f=154&t=101670

Reproducible: Sometimes

Steps to Reproduce:
Sorry, no idea. I startet out with an new kde installation.


Expected Results:  
Smooth file indexing.

The e-mail indexing in disabled, file indexing is enabled.