I have the same issue, but I noticed the sealer at the base of the shower(where it meets the wall) is peeling away exposing a small crack. Since it is a small crack, hopefully a litte dab of sealer will fix this.

You piggybacked on a 5 year old thread so I gave you your very own.
What type of shower do you have? Manufactured enclosure or a custom tile shower? Caulk the crack with Silicon Jel and let me know if that helps answer my questions, I need more details. Once I know what you have we can began to make a repair. Regards, Tom