Can't Delete Flat file off of lun

I just finished deloying 130 VMs' on a 1.8tb lun - During my deployment I had a few fail - the left behind corrupt vmdk.flat files. I have tried to delete these file from within system center and it tells me that the file is in use or busy. I use putty and ssh - use the rm command and still the file is in use or busy, I can however rename the file. I can move the file to a another directory. I JUST CAN DELETE THEM AND IT'S DRIVING ME OUT OF MY MIND

any help would be great - thank you

ALMOST INSANE