have you got the manuals, where they say what "SEr" means? I've got the same kind of hardware, and it gives the same error, but mine is really fu-bar. I've opened it, it's not that difficult, just be sure you removed the battery and allowed the condensators to unload because you can get a not dangerous yet scary shock otherwise, possibly making you drop the camera... unscrew all screws and remove the front panel, keep the battery door open and lift the cover on that side first.
if, as you say, it's the zoom not moving, then it seems an easy guess that the zoom is the problem. if that's so, then you might be lucky and it's just a matter of some connector moving out of its plug or you're unlucky and it's one of the tiny weak plastic support of three metal points which fit into the zoom mechanism. if one of those is broken, I don't think it's possible to repair the camera.
when you remove the front panel, be careful when you take the lens cover away: it fits onto the zoom body clicking on it by ways of three tiny weak plastic clips. try not to break more than one of them, otherwise it will be difficult to get it back in place. there is a very simple locking mechanism to keep the flat connector in the microsocket.
hth,
Mario
Mario Frasca
June 2005