OK, here's the pitch (if I can remeber how to spell):
Much time was devoted to the crafting of a mission, and the result was both pleasing to the eye and apparently bug-free.
The problem arose when I substituted Dark's Apollo conversion for the Lokis I had been using. Now, when ever I load the mission, it pops up a pathetic error message about 'argument count is illegal in sexpression "when"', and telling me that 'when' is an illegal argument. Anyway, I have seen this error before, on a mission that had grown unstable due to its size, but this mission is neither huge nor otherwise resource-stressing. Apart fomr the error message, the mission runs fine if you hit the continue button.
I immedietely replaced the Lokis, but the error remains. Assuming the Apollo caused the bug (the ship worked fine when I made some test missions), why has hte error not disappeared?
One point that may be relavent is that the Apollo's description does not appear in the tech database, even though I have tripple-checked the tbl entry. Are these two facts indicative of some deeper problem with the Apollo (I don't think it is, since removing the tbl entry had no effect on the mission error), or is my mission simply screwed.
If the mission is screwed beyond repair, how best to salvage it? The code is otherwise fine, so what's the quickest way to transfer everything to a new mission file? And if anybody suggests redoing it from scratch, I'll cry

Standing by...
[EDIT] Just so there's no confusion, I'm not knocking Dark's work. His stuff is consistently superb, and no doubt the fault is at my end.