Imac is still crashing with version 9.1.5

Hi

my Imac is still crashing with version 9.1.5. cant be good for the mac so will have to look at uninstalling again. has noone else had this problem?

Anonymous UUID: 7544B4B1-82B0-C205-52C0-63AE1EA29DE5

Tue Oct 14 01:01:56 2014
panic(cpu 2 caller 0xffffff800d1db680): "vnode_rele_ext: vp 0xffffff804ffc5b40 usecount -ve : -1. v_tag = 16, v_type = 1, v_flag = 84800."@/SourceCache/xnu/xnu-2422.115.4/bsd/vfs/vfs_subr.c:1788
Backtrace (CPU 2), Frame : Return Address
0xffffff82d9beb5d0 : 0xffffff800d022f79
0xffffff82d9beb650 : 0xffffff800d1db680
0xffffff82d9beb690 : 0xffffff7f8e7e35cb
0xffffff82d9beb6b0 : 0xffffff7f8e7e2e34
0xffffff82d9beb9e0 : 0xffffff7f8e7e4ea8
0xffffff82d9beba20 : 0xffffff800d3b6271
0xffffff82d9beba80 : 0xffffff800d1e055d
0xffffff82d9bebad0 : 0xffffff800d1f50e0
0xffffff82d9bebb70 : 0xffffff800d1e6c65
0xffffff82d9bebc20 : 0xffffff800d1e7522
0xffffff82d9bebf50 : 0xffffff800d440c63
0xffffff82d9bebfb0 : 0xffffff800d0f4176
Kernel Extensions in backtrace:
com.sophos.kext.sav(9.1.55)[00000000-0000-0000-0000-000000000000]@0xffffff7f8e7e2000->0xffffff7f8e7e6fff