I'm seeing the same problem you are - only one thumbnail in Firefox 18.0.2. No problem in Chrome 24 or IE9. I suspect it's some sort of problem with the latest version of Flash, but only dhina will be able to track it down. I'd suggest contacting him on the FotoPlayer site.
(BTW, Java is never required for viewing an album, so you can ignore that completely.)
I've now worked out that when I completely uninstall Flash ver 11.5.502.149 and roll back to ver 10.3.183.50, the thumbnails appear properly in Firefox. I have now updated flash back to the latest version and the problem is back again.
Dhina has come up with several suggestions and thinks that it is a problem with my hosting.
However, it seems that some people can see these thumbnails and some can't. I would therefore appreciate it, if anyone could test this out on Firefox and report back on here.
The page is here .
I see them with IE10, and Chrome 25 but not with FF19.
I'm not sure that this represents an "answer" to the problem, but as of today there no longer seems to be a problem viewing these thumbnails on firefox.
There were some microsoft windows updates this morning and I don't know if the resolution to this firefox problem had anything to do with this.
Thanks for everyone's input.