My Error Logs + Login Issue

[muhsinb]

When going through my error logs, why do i get alot of messages as follows:

 

[Wed Mar 07 14:44:18 2007] [error] [client 84.252.26.161] PHP Warning: main(includes/boxes/header_tags.php): failed to open stream: No such file or directory in /var/www/html/includes/column_left.php on line 29, referer: http://www.mywebsite.co.uk/product.html?os...33ea87913e8cdfd

 

Not sure what it means...the product however seems to work and appear fine?

 

Also, i have a slight problem in regards to logging in.

 

When i login via the "My Account" link in the Top Header Navigation, i can login fine. I then logout then can also log back in just fine.

 

However, if i try to login from the homepage link, the "log myself in" link, then the first time i can login fine. I logout, but when i log back in, i get an error message sending me a link to my host. I have no idea whats happening here. I've contacted the host and they reckon it is nothing to do with them and to be honest, i dont think its nothing wrong with there side

 

Am using shared SSL. Is it possibly something to do with session ids or cache or whatever?

 

Thanks