PHP Fatal error: Call to undefined function theme_link() in plugins/content/link/nodereference_explorer_plugin_content_link.inc

Problem

I had a blank page, sometimes (clearing cache solved the problem for some minutes but error reappaears after), when creating a node containing several nodereference_explorer fields. I looked in php log and saw this error:

PHP Fatal error: Call to undefined function theme_link() in nodereference_explorer/plugins/content/link/nodereference_explorer_plugin_content_link.inc on line 73

Proposed resolution

I have solved it with the joined patch, but not sure it is the good way to fix it...
In file plugins/content/link/nodereference_explorer_plugin_content_link.inc, I have added code below just after line 9: module_load_include('inc', NODE_REFERENCE_EXPLORER_MODULE_NAME, 'plugins/content/nodereference_explorer_plugin_content');

// Fix php fatal error "Call to undefined function theme_link()" called in function theme_nodereference_explorer
// happening sometimes : clear cache and it's ok,
// try later without clearing cache and Fatal error
if ( !function_exists('theme_link') ) {
  module_load_include('inc', 'link', 'link.theme');
}

Details :

• Pressflow 6.27
• memcache used
• php 5.2.6-1+lenny16