SSH to your ESXi and list PCI devices: lspci -v | grep -e Ethernet
See if your 5 vmnics are showing up there.
Are they listed in the command: esxcfg-nics -l
Check your IBM server console in the IMM or IMMv2, the physical nics are showing up? Are they up/down?
If they are down, most probably it's not a VMware issue, you might need to check your physical switch port and cabling.
If they are up, you might want to have a look at driver versions in the VMware HCL and check for compatibility issues.