1. download !latest! driver from areca-ftp ftp://areca.starline.de/ (mirror germany)
-> areca has newer driver for ESX5.x ,maybe try beta it will fix some problems
2. copy it on the esx host
3a. esxcli system maintenanceMode set --enable true
3b. run: localcli software vib install --no-sig-check –v scsi-arcmsr-1.20.00.15.vmk5.130419-1vmw.500.0.0.472560.x86_64.vib
4. reboot
5. esxcli system maintenanceMode set --enable false