summary indexing blocked and binary file warning

I noticed that my summary indexing stopped working. The summary results files are being generated in the spooler, but are not indexed.

my /opt/splunk/var/spool/splunk/ folder is full of file like *.stash_new that are filling my disk. and in splunkd.log I found :

12-20-2012 20:23:09.780 +0000 WARN FileClassifierManager - The file '/opt/splunk/var/spool/splunk/aejhsdv_342014304.stash_new' is invalid. Reason: binary