In my experience "Error code 25" is usually relating to the signal from the dish being corrupted before reaching the box, some channels are usually ok but the weaker ones just kick up the error 25 message. Most of the times I have encountered this it has been the F Connector that connects the co-axial cable to the box not being correctly fitted, like wise it could always be at the LNB also but is more likely near the digibox as they are more likely to be moved etc.
Of course it can be a multitude of other things but this is usually the cause.
1 x Sky HD, 2 x Sky +, 1 x Sky Digital,
Hope this helps anyone...