What does the black money bag icon that rotates over buildings in Tropico 3 mean?
"It means that teamsters haven't been moving goods into/out of the building. For basic industry, this means that output goods aren't being removed, for second tier industry it can mean the same or that it isn't having input goods moved to it. Generally the cause of this is because you don't have enough teamsters, they aren't spending enough time on the job as opposed to fulfilling their needs, or that they can't reach the building efficiently."
Credit to - http://www.gamerswithjobs.com/node/46864?page=3 User Tannhauser
"It means nothing has been outputted from that facility in the last year. In the case of farms it may be due to the farm still growing the product, in the case of factories, it could be that it hasn't been supplied any materials to create it's product and or there isn't any workers at that facility." Credit to - http://forum.kalypsomedia.com/showthread.php?tid=2509, user City Builder
I've seen farms, logging camps, and other lowest-level production buildings with this icon over them, even if they have zero output goods.