The block X was assigned to the invalid region footer and has been disabled I am seeing the following:

The block X was assigned to the invalid region footer and has been disabled.
The block Y was assigned to the invalid region footer and has been disabled.
The block Z was assigned to the invalid region footer and has been disabled.
The block W was assigned to the invalid region search and has been disabled.

Here is my code 

array(
  'module' =&gt; 'W',
  'delta' =&gt; 'form',
  'theme' =&gt; $admin_theme,
  'status' =&gt; 1,
  'weight' =&gt; 0,
  'region' =&gt; 'search',
  'pages' =&gt; '',
  'cache' =&gt; -1,
  'visibility' =&gt; BLOCK_VISIBILITY_NOTLISTED,
),
array(
  'module' =&gt; 'X',
  'delta' =&gt; '1',
  'theme' =&gt; $admin_theme,
  'status' =&gt; true,
  'weight' =&gt; 0,
  'region' =&gt; 'footer',
  'pages' =&gt; '',
  'cache'  =&gt; -1,
  'visibility' =&gt; BLOCK_VISIBILITY_NOTLISTED,
),
array(
  'module' =&gt; 'Y',
  'delta' =&gt; '2',
  'theme' =&gt; $admin_theme,
  'status' =&gt; true,
  'weight' =&gt; 0,
  'region' =&gt; 'footer',
  'pages' =&gt; '',
  'cache'  =&gt; -1,
  'visibility' =&gt; BLOCK_VISIBILITY_NOTLISTED,
),
array(
  'module' =&gt; 'Z',
  'delta' =&gt; '3',
  'theme' =&gt; $admin_theme,
  'status' =&gt; true,
  'weight' =&gt; 0,
  'region' =&gt; 'footer',
  'pages' =&gt; '',
  'cache'  =&gt; -1,
  'visibility' =&gt; BLOCK_VISIBILITY_NOTLISTED,
),


);

Any suggestion greatly appreciate it. I have other blocks that have properly worked using this method with the custom theme. But the above in $admin_theme = 'seven'; are not working.
It doesn't work because regions are theme specific. The only way you can have cross theme block export/import is to have the same regions (machine name) defined in your admin theme.