D.A.
Can you relax + take it easy on her? She's only 4. Some kids have bed wetting problems into their tweens....
Don't act so upset when she does wet the bed....you may be giving her more of a Psychological complex that will only cause more problems later in this area.
How about just put her in a PULL UP or something for the nights that she can't make it the whole night (or every night until she does go dry through the night)?
How do you think she can control this if she is peeing in her sleep?