Why can't I delete groups in Sharepoint Foundation 2010?

I have a test group I created in SharePoint that I want to delete (I'm the only user in the group). In the "People and Groups: All Groups" screen I click the edit icon next to the group and then click on the "Delete" button and ok the following warning dialog. However, the group doesn't get deleted. Any idea why this is happening and how to finally delete this group? T开发者_JAVA百科hanks.

See this related question on the Sharepoint StackExchange. Only the site collection administrator is able to delete groups.