thanks for your reply
I put an info file up,
http://test.sigmahotels.com/info.phpto display the PHP settings,
you could be right, its a php timeout, I just wondered why SQLyog reports the export has been completed, I would expect it do detect the error, and report it.
erm to give you more info
I am using the free version, as a client side GUI, the database is on my hosting provider's server, I have a 256/64 ADSL connection, living Cyprus so its not so high tech here

I also get a lot of lost connection to mysql problems, i managed in the end to upload the table, my using a previous dump I had taken with mysql front, and editing that, it was about 6 meg, 25,000 rows, uploading with sqlyog caused many failures due to lost connection, however by using the error log, I was able to edit the .sql file to remove rows already inserted and continue with a smaller file, doing this about 5 times I managed to get all the data in. Of course this won't help me taking large dumps, I have a similar problem with phpmyadmin, it times out after 300 secs so I get a partial dump. As my provider doesn't give SSL access the option of using command line SQL commands to take a dump to the server and zip it and ftp it down is not available, but I do need to find a way to take full backups as this a commercial site and the hosting company only does backups weekly, maybe I need a better hosting provider

Thanks for you help anyway, all suggestions welcome
@mark - please use the Forums - simply because then not only one person will be able to help you then!