The dtstart and dtend are indeed in m/d/Y in your csv. You could try either switching the importer code over to m/d/Y or just adjusting your csv to match d/m/Y
your csv is tab delimited. (csv stands for Comma Separated Values!)my interpretation of the importer code is that it should be able to handle tab delimiters (the csv import library dynamically detects the delimiter), but is not a scenario I have tested. Play it safe and stick with commas? If you have commas in your event, this appears to be ok, so long as the field is surrounded by double quotes (as per the 'categories' field in my example CSV
You mention you are producing your CSV from Excel, and this is probably the cause of your headaches:
try my suggestions above, which are
1) format the dtstart and dtend cells in Excel to be custom number format dd/mm/yyyy hh:mm:ss
1) export from excel in .csv (MS-DOS) format
make sure to examine your output csv file in Notepad or other text editor to check for proper formatting.