Multiple loops older/ newer posts problem

I have a wordpress themplate working with 4 loops. Every loop is a category and has its own collumn (this is the site
Now I would like to show a button ‘older’ and ‘newer’ posts on the bottom of the page and limit all the columns to 10 posts. Since I’m a very poor coder I really need some help with this one.
In Addition I have another problem, the standard wordpress search widget does’nt work and always redirects back to the home page. This has something to do with the query but I have no idea what.
I’ll give you the code so you can check it and give some tips to clean it up.

Thanks in advance!

[code moderated as per forum rules - please use the pastebin]