Modify the command button text to be something like this:
'If JobNo is numeric...
DoCmd.OpenReport "rptMyReport", , , "[JobNo] = " & Me!txtJobNo
'If JobNo is alpha...
DoCmd.OpenReport "rptMyReport", , , "[JobNo] = """ & Me!txtJobNo & """"
...where Me!txtJobNo is the textbox that contains the job number in question.
This kind of question (unrelated to the book) should be directed to the appropriate forum. I suggest posting such future questions to the Microsoft product-specific newsgroups. See the following page for instructions on how to connect to the Microsoft newsgroups.
http://www.pacificdb.com.au/MVP/newsgroup.htm
Graham R Seach
Microsoft Access MVP