Try to response.write SESSION("web_num"), and see if that hold any value.
A better way is to try this.
pb_SQL = "SELECT * FROM web_1 WHERE web_num= '" & SESSION("web_num") & "'"
pb_RS.Open pb_SQL, objConn, , adLockOptimistic
Now copy/paste the resulting SQL statement and execute that on query analyser and see what it results, that would give you some idea on what is going wrong. Also confirm if you are using any Loop to do your update there.
Hope that helps.
- Vijay G
Strive for Perfection