Couple of wordpress problems. Help please!

Hi,

I have 2 problems I need some help with.

1) Everytime I write a post and press save or publish, I am sent to this page with the following message:

“Warning: weblog_ping(/home/bangkokh/public_html/bangkokfinder/blog/wp-includes/class-IXR.php) [function.weblog-ping]: failed to open stream: No such file or directory in /home/bangkokh/public_html/bangkokfinder/blog/wp-includes/functions.php on line 880

Warning: weblog_ping() [function.include]: Failed opening ‘/home/bangkokh/public_html/bangkokfinder/blog/wp-includes/class-IXR.php’ for inclusion (include_path=’.:/usr/lib/php:/usr/local/lib/php’) in /home/bangkokh/public_html/bangkokfinder/blog/wp-includes/functions.php on line 880

Fatal error: Cannot instantiate non-existent class: ixr_client in /home/bangkokh/public_html/bangkokfinder/blog/wp-includes/functions.php on line 883″

The post appears fine when I view the page so why am I getting this error?

2) I cannot connect to the various pages and category links. If you go to my URL: http://www.bangkokfinder.com/blog you will see what I mean. Click on any of my navigation or catergory links and it will not load. Says page not found.

I recently created a .htaccess file in the root folder and changed the permissions accordingly. But I haven’t written anything on it except went into my wordpress dashboard and changed the permalinks tags structure to /%category%/%postname%/

Do I need to do anything with the .htaccess file since 1) the file was created after most of my posts. 2) the file was created after I changed the permalinks tag.

Any advice would be most appreciated. Again the URL in question is http://www.bangkokfinder.com/blog

Cheers!