um, it is important. I am not exactly sure how important, but I don't thing will work right without it.
I suggest trying a repair on the "SolarWinds Orion Core Services" and "SolarWinds Orion Network Performance Monitor" from "Add/Remove"/"Programs and Features" and re-running the config wizard.
What version are you on? 10.1.2? If not, (*edit* it helps when you read) upgrade to that too. If all that fails, open a ticket.
oh, also, how much free space do you have? at least some in DB drive(s), os drive, and iis drive. is sql allowing DB to expand?
I am just throwing out generic solutions nothing specific to your reported issue