Of any possible curse to have, I'll take the "problems due to winning millions" one.
My dad told me about a prank his work friends played on a guy that was getting married. They bought him a lottery ticket (they all play lottery pools together) and had a recording of those being the winning numbers that night and played it for him during his bachelor party... they told him "I bet you can't wait to tell your fiance!" He's like "Fiance? **ck that slag I'm rich now!" (I'm paraphrasing)... Imagine how bad you'll feel after you find out it was all a prank, and you still have to marry her the next day.
I can see how it would ruin marriages and family relationships though.. Hard not to have a wondering eye when you're mega rich and can get (almost) anything/anyone you want. Family/Friends will probably want money, if you give some they will want more, or hear that another got more, or be mad they got less, rinse and repeat til you're broke or hated.