enter parameter value

hello



i have the following code



Dim str As String

str = "select combination from tbl_userinformation where Username= txtuser.value AND actualdate=txtdate.value ; "

If DCount("*", "tbl_userinformation", " [05-Henrichpiramid]=true AND " & _

"Username = '" & Me![txtuser] & _

"' AND [actualdate] = " & Format(Me![txtdate], "\#mm\/dd\/yyyy\#")) > 0 Then

DoCmd.RunSQL (" update tbl_userinformation SET combination = str &'05-Henrichpiramid' where Username= txtuser.value AND actualdate=txtdate.value ;")



but when i run it it asks me for enter parameter value for str

can you help me please?

i don't know what my problem is

thank you

enter parameter value