check that EventEndDay1 and EventStartDay1 are actually the names of the columns in your table given you have enclosed them in [ ], they coudl possibly be control names I suppose, but not sure about that.
the fact that you are being requested to enter values suggests to me they are not.
I'm a litle leery seeing a column called EventEndDay1, which suggests there may be a EventEndDay2...n
also seeign a column called EventStartTimeDay suggests you may not be clear as to how Access / JET stroes dates/times. like mosts db systems date time values are stored as a single entity/ the actual representation is platform/db specific. I JET's case its the number of ticks since a becnhmark date IIRC 01 Jan 1900, which is stored as an integer. the time element is stroed as the number of seconds since midnight, stored as decimals.
so .25 is six hours, .5 is 12 hours 1/86400 is one second (or if you prefer 1/(60*60*24))
using datediff is the correct way to date/time arithmetic but you can just as easily subtract one date from the other, althoughits a clarty way of dong it, Access/Jet allows you to do so as the actual mechanism of storage is a number.
so fdirst off chaeck to findout why the values you thing are date time are not.... my guess is they are either missplet of they are not oin the current scope of the project
I'd rather be riding on the Tiger 800 or the Norton