I have an excel worksheet with column A containing dates and column B containing the respective days. Eg. A2=01/01/14 and B2=Wed and so on.
Im trying to retrieve th
VLookup is sensitive to data types. And your VBA routine is looking for a DATE data type, but such does not exist on an Excel worksheet. So you need to convert your string lookup_value to a data type compatible with what is on the worksheet. This could be a Long (for whole dates) or Double (if you are including times.
Try:
the_day = WorksheetFunction.VLookup(CLng(CDate(lookup_value)), lookup_table, 2, False)