Check if the hosting company has correctly installed GD library. If you went to GoDaddy, this is one of the issues you should resolve per topics I saw at WP.org. Contact hosting tech support wherever you’re hosted.
Vhosts location is not something referred to or stored in a database it is something purely resolved by the web server and before any web application starts work as such.
There are many aspects to a server config that might differ mercime points to one in the GD library being a required module and compiled in some versions of PHP and not in others also the horror known as ‘safe mode’ may be set and if so needs to be unset.
Making a folder or directory writable is only half the story and often thought all that’s required but in reality it doesn’t matter what you set permissions to if the necessary system users do not have access to the ‘group’ or are not the ‘owner’ but this is best left to your host to sort out.
Thanks for the replies guys.
It’s my own dedicated server, and I run 10+ wordpress sites from it, so I’m sure it’s not a problem with the GD library (images a generated no problem). I also checked to make sure that php safe mode wasn’t enabled.
All current avatars fail to show, indicating that buddypress is looking in the wrong location (they have been uploaded). It fails at the upload, not the generation stage.
I’m sure it’s something to do with the transfer, as I’m sure buddypress would run fine on my server from a standard installation.
My new DOCUMENT_ROOT is /var/www/vhosts/paintballpimp.co.uk/httpdocs .. which is different from the other server, and I suspect this might be causing the problem. This value must be stored somewhere in the database or settings?
Thanks again guys
Iv’e just looked through my error log files, which show:
[Fri Mar 25 16:54:37 2011] [error] [client 86.129.189.123] PHP Warning: file_exists() [function.file-exists]: open_basedir restriction in effect. File(/group-avatars/11) is not within the allowed path(s): (/var/www/vhosts/paintballpimp.co.uk/httpdocs:/tmp) in /var/www/vhosts/paintballpimp.co.uk/httpdocs/wp-content/plugins/buddypress/bp-core/bp-core-avatars.php on line 150
[Fri Mar 25 16:54:37 2011] [error] [client 86.129.189.123] PHP Warning: file_exists() [function.file-exists]: open_basedir restriction in effect. File(/avatars/23) is not within the allowed path(s): (/var/www/vhosts/paintballpimp.co.uk/httpdocs:/tmp) in /var/www/vhosts/paintballpimp.co.uk/httpdocs/wp-content/plugins/buddypress/bp-core/bp-core-avatars.php on line 150
[Fri Mar 25 16:54:37 2011] [error] [client 86.129.189.123] PHP Warning: file_exists() [function.file-exists]: open_basedir restriction in effect. File(/avatars/27) is not within the allowed path(s): (/var/www/vhosts/paintballpimp.co.uk/httpdocs:/tmp) in /var/www/vhosts/paintballpimp.co.uk/httpdocs/wp-content/plugins/buddypress/bp-core/bp-core-avatars.php on line 150
[Fri Mar 25 16:54:37 2011] [error] [client 86.129.189.123] PHP Warning: file_exists() [function.file-exists]: open_basedir restriction in effect. File(/avatars/3) is not within the allowed path(s): (/var/www/vhosts/paintballpimp.co.uk/httpdocs:/tmp) in /var/www/vhosts/paintballpimp.co.uk/httpdocs/wp-content/plugins/buddypress/bp-core/bp-core-avatars.php on line 150
Pretty sure this is the problem, I just don’t know what it means.
That’s ‘Safe Mode’!
Are you running one of those control panels like Plesk *he shudders* 
Yeah I am lol. Plesk.
It does sound like it yeah, very strange though as I’ve never had any problems with my other sites.
Going to give this a try: http://www.bigsoft.co.uk/blog/index.php/2007/12/30/fixing-php-s-require-open_basedir-restri
