In Gambit, what does this mean:

"Meshing volume volume.4 aborted because it has invalid topology."

Is there anyway to mesh a volume with this statement.

Maybe are there virtual faces or lines that aren't connected? Otherwise I don't know! Good luck!

maybe your grid is not consistent

I have had problems in the past that seemed like yours, an error message that I didn't understand and no way to mesh the volume. My solution to the problem was to check all the vertices. It is possible that you inadvertently created multiple vertices at the same or nearly same location. Subsequently weird and open volumes are created from these vertices if you don't know they are there. So do this:

go to the 'Summarize Vertices' panel, and shift-leftclick on a vertex. Note the vertex number and then shift-middleclick on that same vertex. Check if the number changes, if it does then you're in trouble.