ATTENTION! Pure (unoptimized) backend kernels selected.

[pdo]

Ok, well it's not an error, it's telling you that you're using a "pure" kernel to crack your hash. There are good reasons to use a pure kernel, but it's going to be slower than using an "optimized" kernel. The message then says if you want to use an optimized kernel, you can add "-O" to your command line.

Good luck.

yes, i don't understand the error