Runtime Error #7 Out Of Memory

My Dell 410 is running Windows Vista Premium Home ed. it has 2 GB installed memory of which about 1.07 GB is available. We have been running a geneology database program called 'Legacy' without any problems since upgrading to Vista in April. Yesterday (8/8/07) we get the message: Runtime Error #7 Out of Memory whenever we click on the Legacy icon.

 

Sweeps for viral infection and/or spyware have come up clean. We have not added equipment or programs for some time. Anyone else have this problem?