Help me someone….

McAffee AV disable automatically. Why?
Please help, someone there. I encountered a problem with Mcaffee AV software. Each time i enable it on my NT server it automatically disable. When i check on the application log i found out that it has error.
It also happen on my Win98 workstation. When i do scanning it prompt out an error message. That mean entire company are not protected from virus attack.

following are the error:
Exception in Mcshield.Exe
Exception details follow:
Build 402abranch / 1.75
Crash address 0x0152088ff
code 0xc0000005
Flags 0x00000000
2 Parameters : 0x00000000 0x00000000
Object being scanned = \device\harddisk0\Partition1\WINNT\isadmin.ini
( @ 4)

I am appreciate if anyone can help me.Please