[tw] "It's not possible to save changes" on a network drive

All - I'm trying to set up a TW on a network drive, and getting the "It's not..." error. Details: IE 6.0, SP3. BUT when I check the file properties, I see only the Read Only and Hidden attributes - there's no Blocked button or attribute. There are no odd characters or spaces in the directory:

[tw] It's not possible to save changes....

I've read this http://groups.google.com/group/TiddlyWiki/browse_frm/thread/b9aa0bd891bf05b1/91554e358fb6186c?lnk=gst&q=its+not+possible+to+save+changes#91554e358fb6186c and this http://groups.google.com/group/TiddlyWiki/browse_frm/thread/482cd99a06bdf39c/102c40472656dee1?lnk=gst&q=its+not+possi