on the button that sends the request you'd just have to have something like this
Code:
dim sMsg as string
sMsg = ""
if Special_Price1 = "Yes" and nz(Special_Price1_Qty) = 0 Then sMsg = "Value missing for Special Price Marked yes on Item " & <field name with special price item description> & vbcrlf
blah blah for each check
Msgbox "Can not forward order. These items are in error: " & vbcrlf & vbcrlf & smsg
I don't know how your form is set up but you can do some things to mitigate the amount of code you have to write but i"d have to see a sample of the database to go in that direction.