Links in Posts Before New Years Not Working

Hi, my website is https://www.dauntlessjaunter.com. I seems to be having a problem with my WordPress site. I was looking on my Google’s Webmaster’s Tools today, and it showed the crawler chart, where prior to Jan 1, 2012, I had less than 50 crawler errors, and on Jan 1st until now it skyrocketed up to over 1,000 errors! I clicked on some of them to see what’s wrong, and some of my posts have links in them that don’t work.

For example, here is a post from just before the New Year.

It is something of a travel guide, and none of the links to any of the sites I listed work. They all have a prefix that is the post link, so it looks like this: https://www.dauntlessjaunter.com/2011/12/30/if-you-go-frankfurt-germany/www.palmengarten.de .

I am quite sure that it was working when I posted it, and I was trying to think back to remember if I had made any changes on New Years, but I can’t recall any. Also, my site has various tags and other 404 pages for some reason, all starting on the same day, Jan 1, 2012. Any ideas as to what might be wrong? Thanks so much in advance!