I have a WordPress blog I've migrated from another CMS, and I've being having a lot of problems with my permalinks structure: lots of articles give a 404, although they are there, somewhere, published.

The site is www.muycomputerpro.com (MCP for short), and for example an article that should be found is: http://muycomputerpro.com/Actualidad/Especiales/2009-las-grandes-crecen-en-la-bolsa

If I do a search on the search tool at MCP, the result is there (see EnlacesMCP-1.jpg)

But when I click on the link, our 404 error page appears (see EnlacesMCP-2.jpg)

The weird thing is, the article is published, and the permalink is the right one, as you can see on this screenshot of the WordPress CMS:

The permalink (below the title) is correct (http://www.muycomputerpro.com/Actualidad/Especiales/2009-las-grandes-crecen-en-la-bolsa/)

but it does not work. In fact, if I try to use the short link (http://www.muycomputerpro.com/?p=5023) the article does not show either.

I've accessed my WordPress DB and I've search the article to see if there is something wrong there, but from what I can tell all the fields are OK, here's a screenshot:

I really don't know what is causing this. The permalink structure should work (I'm using the "Custom permalink" plugin to preserve the old URLs that had a alphanumeric code at the end of the postname) and the permalink config on wordpress is "/%postname%/".

I really need help :(