slic3r broken in ubuntu/mint 64

I've been using slic3r on ubuntu64 for a while now, but it is now unable to generate gcode for known STL files.
I get this error in a pop-up

Argument "\x{25}\x{35}..." isn't numeric in numeric gt (>) at /home/scott/local/pkg/Slic3r-0.9.8/lib/std/Slic3r/Layer/Region.pm line 255.

I tried using 0.9.7 and 0.9.5. The former gives a similar error and the latter just crashed.
There must have been some package update that broke this but im not too sure.
I hope someone has a guess whats wrong, my toolchain is broken and I've got stuff to print!
Thanks in advance.

Although I have no experience of Ubuntu and slic3r, this looks to be a problem with your config files. When upgrading slic3r, you tend to need to delete the .ini files as they don't appear to be transferable form one version to the next.

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Using ABSPrusa Mendel Zaphod with Pronterface and slic3r 1.3.0. Printing well with 3mm PLA and ABS through 2 x J Head Mk IV b and Wade Geared Exruders. Controlled using RAMPS1.4 board running Marlin_v1.1.9

Thanks Moto, i dont recall that being an issue in the past, but it makes sense. It Would be nice if slic3r could check for incompatable configs and give a meaningful error.