Word that describes someone that causes his own misfortune

Solution 1:

Consider self-defeating

causing the same problems that you were intending to solve

Solution 2:

I suggest hapless (from Merriam-Webster):

: having no luck : unfortunate

listed synonyms: unlucky, hard-luck, ill-fated, ill-starred, jinxed, luckless, snakebit (or snakebitten), star-crossed, unfortunate, unhappy

Solution 3:

In addition to hapless, as suggested by Cornbread Ninja, I'd also suggest inept carries similar connotations (from the Random House Dictionary, via Dictionary.com):-

1. without skill or aptitude for a particular task or assignment; maladroit: He is inept at mechanical tasks. She is inept at dealing with people.
2. generally awkward or clumsy; haplessly incompetent.
3. inappropriate; unsuitable; out of place.
4. absurd or foolish: an inept remark.

Inept carries with it the idea that one has voluntarily exposed oneself to the sort of situation where these things apply.