PAE is Physical Address Extension: https://en.wikipedia.org/wiki/Physical_Address_Extension
This is only for IA-32 (the 32-bit processor type, also called "x86"), not AMD64 (the 64-bit variant of IA-32, also called "x86-64"), so if you have a 64-bit processor, you can (and should) use the 64-bit Trisquel. I don't know whether or not any AMD64 processors without PAE support exist.
If you really have a 32-bit processor without PAE support, you'll need to get a distro with PAE disabled. Supposedly[1] these are usually labelled "i386", "i486", or "retro". Maybe gNewSense would be an option (I can't check since the gNewSense website isn't loading for me at the moment).
[1] https://en.wikipedia.org/wiki/Physical_Address_Extension#Linux
