install windows server 2012 r2 in r730xd use usb flash

hi all 

i have server R730xd without DVD and i want to install  windows server 2012 R2 use usb flash i configure the raid 5 and burn iso to flash ,when i reboot the server to install windows, installation begin But told me that windows could not collect information for osimage install.wim does not exist .

how can i solve this as soon as

thanks