Sometimes you need to set the classpath for the driver in the jboss run.bat file. You can try this.
Hope this helps
You will need to provide more of a description of your problem.
Which JBoss version are you using?
Post the actual error and stack trace.
What do you mean by 'a page that requires DataBase connectivity'? Are your pages executing SQL? Are your pages accessing entity beans? Are your pages using Hibernate objects?