file server problems

we are runnning 4 2003 servers 2 are R2 and clustered and we are having a few problems.

when we try to copy some large ~1gb files from the server we get a message: cannot copy file 8888888.888 not enough storage space avaiable to process the command.

smaller files copy ok.

we are running 2003 file servers running FC cards. we had this problem a few weeks ago and now its happening as we roll in new servers to replace the old ones.