As explained in the FAQ:
Why can't I view my gallery on a 3G mobile connection?
... it is not the gallery itself that is the problem, but the content modification carried out by the 3G provider which will break not only SimpleViewer galleries but other JavaScript-based websites.
Unfortunately, we have not found a solution to this problem yet and all I can suggest at the moment for 3G users would be to contact their providers to see if content modification can be turned off on their accounts.
Our other mobile-friendly image viewer, Juicebox, also relies on JavaScript and will not display on a 3G connection.
The recommended method of embedding our Flash image viewers (AutoViewer, PostcardViewer and TiltViewer) is to use SWFObject and this, being a JavaScript file, is also likely to be broken by content modification.
Steven Speirs
SimpleViewer Support Team