Alright, that looks like it's using GL_REPEAT, so obviously GL_CLAMP_TO_EDGE isn't supported. It was only added in GL 1.2 after all. I've added a workaround for this case by offsetting the texture coordinates half a pixel inwards and leaving the wrap mode untouched on systems that don't support GL_CLAMP_TO_EDGE. I'll upload a new version later.
I've now integrated the final version of this applet into my galleries on my website. I've also added new gallery which is using this for five different environments. http://www.humus.ca/index.php?page=Pictures
It is working fine on my Mac, but my Linux laptop refuses to display anything (after loading the applet). It does have accelerated OpenGL (e.g. Tecplot etc. works fine).
Hmm, did you use the original link or the link to the latest gallery? I deleted the original files and updated the first post just in case to avoid future confusion. I also updated the class files lately with one that's compiled against the lowest possible JVM version, so hopefully it should work on pretty much anything out there. Could you try again, and hold ctrl when reloading to ensure that it doesn't use a cached version?
Btw, I saw a similar problem on my work laptop at first, but after upgrading to the latest java version it worked fine. It was 1.4.2 before, and 1.5.something after. That's why I suspected the JVM version.