From this page, your HOME link reads:
http://www.katianideionizer.com/about.html
Do you have an 'about' page published? it's not finding it if you do. Your HOME link should read
http://www.katianideionizer.com
Your Cost Comparison link reads:
http://www.katianideionizer.com/abou...ompare-RO.html
but you find your page at
http://www.katianideionizer.com/cost_compare-RO.html
Delete the 'about' and it will work. Same is true with the 'aquacultural_comparison like. You have included '/about' in the link.
Delete the 'abouts' and they should work.