Problem with resource monitoring

I added new device (Linux machine). It works fine.
But when i run Test monitor in Disk Utilization (resource monitors) i get message:
The Monitor did not respond to the test request
Summary
Device Name 217.115.203.25
Monitor Name DiskUtilization
Protocol SNMP
OID
.1.3.6.1.2.1.25.2.3.1.6
---
I run MibBrowser and put there this OID, it works (after i loaded HOST-RESOURCES-MIB) and i get these values:
hrStorageUsed.2:998832
hrStorageUsed.3:8
hrStorageUsed.4:321115
..
I tried to increase timeout so i added DATA_COLLECTION_SNMP_TIMEOUT 7 and then even 15 to NmsProcessesBE.conf but it didn't help (Only w8ting for that error message is taking 7 or 15 secs).