deleting Alarms

Hi when I try to delete alarms I get

Failed to perform the operations for the following objects.
Failure Object Reasons
1 IF_DISCARD_936 false

But, the operation is successfully completed for the following objects.
Failure Object
1 IF_UTIL_281
2 xxx.xxx.xxx.xx_Poll
3 IF_UTIL_800
4 IF_UTIL_309
5 IF_UTIL_310
6 IF_DISCARD_293
7 IF-172.16.1.9_Poll
8 IF_DISCARD_911
9 IF-172.16.1.2_Poll
10 IF-192.168.7.2_Poll
11 IF_UTIL_290

how do I correct this problem?

Thank you

Ramzi