@sronsen:
This error message almost always means you have mixed 32-bit and 64-bit libraries on the system. These "unsupported layout" errors have happened before for many other packages besides just Snort, and each time it's caused by having a mix of 32-bit and 64-bit stuff on a system. In particular this error can happen when 64-bit libs wind up on a 32-bit box. I can't tell you how this might have happened, but I'm pretty sure that's what is wrong now.
I had to reformat the drive and reinstall pfSense, but I finally got Snort working. If I could only figure out why the pfSense installation won't work from a USB CDROM, I wouldn't be so put off, but the installation asks for a mount device and fails when a valid one is entered. If I plug in a SATA CDROM drive with the same disc, it just installs to the proper drive without asking me anything. This is on a rack-mounted PC w/o any external bays, so I have to unmount the PC and open it up to rerun the installation. Ugh! I think I'll pass on pfSebse and Snort updates for the next year.
I installed my current config from usb. My 1u system has no optical and I didnt have a usb cdrom. Mine installed just fine using the usb install method.. Maybe try that instead of cdrom?