Update- I installed the new beta for leopard and it is doing exactly the same thing--how can I get it to accept the text file? What am I doing wrong? I exported the calendar file in 3.5 with the default template, and it won't let me import it--it isnot selectable when I go to "import"!

OK, reexported and managed to get it to open the text file, but then got "Event Data Inconsistent" and it refused to import. I tried to edit the file (there was some questionable data) and when I resaved (in Text Edit) it no longer would allow me to select the text file for import. I'm going nuts!