Hi ,
Try with different SCSI devices , 2 devices in one scsi , if you are using more than 200 GB use in seperate scsi
OS DISK - SCSI 0:0
MSDTC and QUORUM - SCSI 1:0 , SCSCI 1:1
OTHER RDM - SCSI 2:0
NEXT - SCSI 3:0
Also check that in EMC the owner of the RDM LUN is changing or not , try to make SPA or SPB some cases if the load on the LUNs increases then it changes from SPA and SPB so that time it may fail.