Not sure about trouble, but I do think you're asking for someone more knowledgeable than I to tell you this isn't officially supported!
stegzzz wrote1) Is my guess at what was happening correct? I don't think start(1).txt was created by google syncing, if google finds a file locked the sync fails.
Nope. Based on
a discussion I found on Google's Product Forums, I think that start(1).txt was indeed created by Google Drive.
stegzzz wrote2) Are there any dokuwiki configuration settings that might be useful to use with a setup like this?
Nothing springs to mind.
stegzzz wrote3) I can tolerate the odd hiccup like the one described above and normally I won't be swapping machines in such quick succession -- I was just testing. However, I don't want to find I've done something stupid that will inevitably lead to big problems e.g. lots of corrupted files etc.
In my opinion, what you're trying to achieve could be worthwhile, but the way you're going about it is likely to lead to problems. DokuWiki won't expect to be fighting Google Drive for control of its files. Perhaps write out what your requirements/goals are, and maybe someone will suggest a more stable way of achieving them.
Edit:
if andi says it'll be OK, then you should listen to him and not to me :-)
For instance, I want a private self-hosted wiki which I can access at my office and on the road, so I run a private wiki in a VirtualBox VM on a server at home, and use Hamachi VPN to access it from the office or from my laptop.
On the other hand, if I understand your setup correctly, your Google Drive idea has one big advantage - if we ignore the sync problems - over my Hamachi setup, which is that you don't need to be connected to the internet for your wiki to work; each workstation has its own full copy of the wiki.