as with most comedies, you have to accept some of the broad strokes (why that is... well, that's another topic for another time).
There are some serious holes here - things that don't really make sense (matters of convenience to move the plot along), and, again, as with most comedies, the splatter gun effect is at work (ie. you throw enough stuff at a wall and some is bound to stick).
That being said, Ricky Gervais is, as usual, extremely funny and almost carries this film by himself (or in spite of himself?).
There are some serious laughs to be held (in that oh, so British way), and some very poignant scenes when the ghosts are released from their purgatory (a very nice touch indeed) - but in between, way too much fumbling and things that either fall flat or don't ring true. The ending, especially, is really weak (from the time that Gervais is hit by a bus until the end of the film).
A truly lame excuse was used to keep Tia away from the convalescing Gervais (not a blood relative, and the hospital has rules, you know!). sigh.
You can tell that good production values were used here - so it had the potential to be so much better, but in the end I can only give it a whisftul smile as I think of how much better it could have been.
(I usually dislike it when a film uses current songs to enforce the emotions on the screen, but I do have to admit that using the Beatles "I'm Looking Through You" was a wonderful choice to introduce the newly dead Kinnear.)