Here is a valuable place to learn about what to do in order to get it working for Linux:
http://www.purebasic.fr/english/viewtop ... et&start=0
BUT...
Following everything I found in these forums, I still am unsuccessful at getting the WebGadget to work.
1) I have BOTH GTK1.2 and 2.0 installed (2.0 was even freshly updated 30 minutes ago via Ubuntu Update)
2) I have libgtkembedmoz.so located under /usr/lib/firefox
3) Created symbolic links to the .so under /usr/lib, /lib, and even in the purebasic libraries folder.
4) ran ldconfig after creating the sym-links
5) I DO NOT have a file /etc/ld.so.config, so I was unable to even try and create this (since I have no clue what should be in it, nor how it should be written), but I did attempt to just add in the /usr/lib/firefox pointer and perform ldconfig.
After performing all these various steps, still NOTHING.
There were a couple of exports you need to do in the README that comes with PB that I also performed.
I even added gtk2 in the command "Library Subsystem" switch in the Compiler Options window. Still nothing.
At this point, I sunk a week into this. All I want to do is see how this cool lil gadget works under linux after using it successfully in Windows. I was frustrated but determined.
I took a stab in the dark here. It seemed it was a matter of PB not being able to link the "libgtkembedmoz.so" file...

#Begin
/usr
/usr/lib
/usr/lib/firefox
#End
Saved the file and closed it up.
Ran a terminal window and did:
sudo ldconfig
Went back into PB and loaded my test...
BAM! Up came the WebGadet!