Query Locked Creating Errors

We are experiencing issues which we would like some help with and causeing serer crashes:

We get a lot of locked queries:

| 2864 | thejobssitecom1 | xxxxx | the_jobs_site_com_1 | Query � | � �4 | Locked � � � � � � � | SELECT SQL_CALC_FOUND_ROWS �wp_posts.ID FROM wp_posts �LEFT JOIN wp_postmeta ON ( wp_posts.ID = wp_p |

can anyone offer a potential reasons why the queries “lock”

Once there are a few queries like this this creates an server error

Perhaps a potential cure? Some settings I may tackle? A better query structure? other Themes seem to work far better with the same level of content.

The jobs board [having tied it on several hosts] seems to have been problematic in this area for some time.

thanks