"I/O Problems detected!" could mean a few things, but outside of normal working hours it typically means that the VMware administrator is doing manual or automated snapshots of the running server, and that can be very bad for Mitel servers. These should be disabled and if snapshots are required the server should be shutdown and then imaged.
A proper reboot of the server should clear the issue, if not, contact support immediately, we have seen this corrupt configuration files that require manual editing and only support should be doing that.
Before rebooting, take a look at Administration - System Information and pay attention to Physical Memory and Disk Swap usage, if Physical Memory is over 75-80% or Disk Swap is over 5%, consider if you have enough resources allocated to this VM.
