How can I unlock a SAN disk in AIX?

I got my LUN mapped to my system, but when I try to create my Volume Group with  mkvg -f vpath100   all I get is an I/O error. What can I do? 
Probably there is still a SAN lock on the disk. Try to unlock it with: 

 # lquerypv -ch /dev/vpath100

and retry to create your Volume Group.