We usually don't recommend sharing the nworks Collector with another application - such as SCOM MS/RMS...but it does depend on how large the VMware environment you are monitoring is. How many Hosts/VMs/Datastores do you have?
Best practice is to have the nworks Collector on a dedicated machine (which can be a VM) - however the nworks Management Center and web UI can be installed on the SCOM MS/RMS. Those components dont have such a high demand on cpu/memory as the Collector.
There is only one hotfix recommended in our Install Guide - it is a Microsoft .Net hotfix http://support.microsoft.com/kb/968760
We have only seen issues in SCOM R2 - you have SCOM SP1 - but in any case you may wish to include this hotfix in your build. Anyway it will prepare you for upgrade to SCOM R2 whenever you plan that
And I definitely recommend you read the documentation
especially the Install Guide - there are a number of pre-requisites including changes to some default SCOM rules, registry changes on the Agent where the Collector is running, and so on.
Hope that answers your question! Any further queries please let me know,