(disclaimer: I generally handle bugs, not legal issues, and can't officially speak on legal matters, so it may be better if you email us directly if you have specific questions.)
Where are the Omni frameworks described as "open source"? I could not find that phrase either on the page you linked to nor the license linked from that page. So perhaps Omni's frameworks don't fit the precise definition established by opensource.org, but they are relatively open, in that you can see the code in them and re-use it in your own applications.
The FAQ on
this page clarifies that if you use our framework in your application, you can still charge money for your application, as long as you give us some credit in your 'About' dialog or wherever is appropriate. The limitation is on selling the frameworks by themselves, without adding some value to them.
Again, please contact us if you have concerns about this. (info@omnigroup.com)