urgent , VSS problem pls help

pls mvp help
my office is using win2003 sp1 , exchange 2003 sp2 , in GC mode , but the
Volume shadow copy service is down
have a big problem , can't start have a error log
eventlog entry:
vss service failed: 2147549183 (0x8000FFFF).
vss service error: 0x80080005

and then the server NTDS Replication also have problem, error code "1864"

when i use VSSadmin can't list , any thing , also show this error , but if i
stop Microsoft Exchange Information Store

this service , then my volume shadow copy will work

i see some site show will the regedit
"HKEY_LOCAL_MACHINE\System\CurrentControlSet\Servi ces\VSS\ "

have problem , but i haven't this , so anyone know about this , pls help

thank your very much