[Solved]: Template error - read the sticky and searched forum, but still not sure

[boxpup]

Hi all,

I've read the sticky post and searched the forum trying to find a fix, but I'm just not understanding a lot of it as I don't know enough about it all.   Would appreciate all the help I can get

I've been getting the below message since swapping host sites:

Template error
Failed to find block 'file_line'(#(<!-- BEGIN file_line -->)(.*?)(<!-- END file_line -->)#s) in

I understand I need to edit the theme.php file in the theme I use as per the sticky.

Can anyone provide a really easy to follow step by step guide for me, and I apologise for being a numpty about all this.   I'm sure the mods are fed up of hearing about this error

I can post the contents of the theme.php file if that helps, plus I'm using a 1.4.2 version (which is very old I know)
I also had a custom link on the site linking back to another page on the site.

Thanks in advance.

[Joachim Müller]

Upgrade! It's absolutely mandatory. Post a link to your gallery!

[boxpup]

Here's the link - http://billypetersen.com/TheGallery/index.php

will work on upgrading today.

[boxpup]

Just to update, we have managed to sort this problem.  All is working fine.

[Joachim Müller]

For the benefit of others with similar issues you should post what you actually did to solve your issues.

[boxpup]

Some files had become corrupt during the backup of the database.   We updated the dns settings to point to the new host.
We then (I had help) backed up the database again from the old host and reinstalled it.   This seemed to resolve the issue.