The most common problem I see is usually in the first 2 rows in the sheet, so
here is kind of a standard approach to match things up.
Common problems: ultimate field/column names in row 1 do not match those in
the table EXACTLY or data in row 1 or 2 is interpretted in the wrong format
for at least one field.
Solution to finding the problem:
Import the spreadsheet into its own new table with the following
modifications made to the sheet:
Make sure row 1 has the field names and insert a new row 2 where each column
has 55 or more x's or any plain text character. This will force all fields to
be interpretted as text, and then the primary error that appears should be
based on the row 1 data that becomes the field names (remember to pick this
on the import wizard).
On the off chance you have any large data in the cells, then you should make
insert 260 x's (or more) to force access to interpret each field as memo. You
can play with this a little to just force memo where required, but it is
usually easier to inspect and track down bad data with text fields.
Once you identifiy the problem usually the rest is easy. Best of luck.