array_merge() Error

Hi there,

I just noticed that one page of my website shows this error:

“Warning: array_merge(): Argument #1 is not an array in […]/wp-content/plugins/user-access-manager/class/UserAccessManager.php on line 1494”

I looked at the php-file and found this function:

if (count($aAllExcludedPosts) > 0) {
$oWpQuery->query_vars[‘post__not_in’] = array_merge(
$oWpQuery->query_vars[‘post__not_in’],
$aAllExcludedPosts
);
Line 1494 is highlighted in italic. This error appears only on one page, not on any other of the pages. As UAM has no specific function on this page, I cannot see why this error appears there. As soon as I log in, the error is gone, but any visitor will see it.
Any ideas how to fix this?

Thanks in advance,
schokopress