Thanks for reporting this issue, we will work on resolving this in a future update.
For now, please try the following workaround: This error only occurs when security is enabled in your project. You can disable security by selecting the option 'Off' in the Project Security dialog. After redeploying, you should again be able to run your project from Eclipse.
For all of you that bumped into this issue, I have good news:
The fix has been shipped in the Mendix 7.11.0 release.
Raise an issue for this at Mendix, cause I expect this to be a V7.9.0 bug.