I was up late, grinding cargo runs for a CG.
Picked up another load of something or other, targeted the destination with my galaxy map, made half a dozen jumps to the destination system, hiked quite a way to the required station, docked at the station, opened up the commodities tab, sold the cargo, selected the supply system on the galaxy map, made half a dozen jumps back again, docked at the supply station, opened the commodities tab, bought more cargo and.....
Eh? What? What's it mean by "Unable to complete transaction"???
After staring at the screen, utterly bewildered, for about 30 seconds, I checked my inventory and found that I was still carrying 500t of cargo which I had, somehow, failed to actually sell and had carried all the way back to where I bought it. [mad][sour]