For numeric values, remove the two "Chr(34) &" in strSQL.

For date values, you need to delimit them with # characters (instead of
Chr(34), which is a double quote). As well, you need to ensure that the date
is in a format that Access will accept. Since you have no control over what
Short Date format your users may have chosen in Regional Settings, that
means it's a good idea to explicitly format the dates so that they'll be
recognized:

       strSQL = strSQL & "[" & Me("Filter" & intCounter).Tag & "] " & " =
" & Format(Me("Filter" & intCounter), "\#yyyy\-mm\-dd\#") & " And "

Now, how you're going to determine when it's text, when it's a number and
when it's a date is more of an issue.

One approach would be to concatenate the data type in the Tag, along with
the Field name. If you've currently got Field1 as the Tag property, you
could use Field1;Text or Field1;Number or Field1;Date instead. You'd then
change your code to something like:

Private Sub Command28_Click()

Dim strSQL As String, intCounter As Integer
Dim varTag As Variant

    'Build SQL String
    For intCounter = 1 To 5
      If Me("Filter" & intCounter) <> "" Then
         varTag = Split(Me("Filter" & intCounter).Tag, ";")
         Select Case varTag(1)
           Case Date
              strSQL = strSQL & "[" & varTag(0) & "] = " & _
                 Format(Me("Filter" & intCounter), "\#yyyy\-mm\-dd\#") &"
And "
           Case Number
              strSQL = strSQL & "[" & varTag(0) & "] = " & _
                 Me("Filter" & intCounter) & " And "
           Case Text
              strSQL = strSQL & "[" & varTag(0) & "] = " & _
                 Chr(34) & Me("Filter" & intCounter) & Chr(34) & " And "
         End Select
      End If
    Next

    If strSQL <> "" Then
       'Strip Last " And "
       strSQL = left(strSQL, (Len(strSQL) - 5))
       'Set the Filter property
       Reports![WorkorderFilterReport].Filter = strSQL
       Reports![WorkorderFilterReport].FilterOn = True
    Else
       Reports![WorkorderFilterReport].FilterOn = False
    End If

End Sub