Plugin cannot creat new directories

site: here

theme:arjuna-x

plugin:event manager

PHP Error Message

Warning: is_dir() [function.is-dir]: open_basedir restriction in effect. File(/) is not within the allowed path(s): (/home/:/usr/lib/php:/tmp) in /home/a5328586/public_html/wp-includes/functions.php on line 2060

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PHP Error Message

Warning: file_exists() [function.file-exists]: open_basedir restriction in effect. File(/) is not within the allowed path(s): (/home/:/usr/lib/php:/tmp) in /home/a5328586/public_html/wp-includes/functions.php on line 2051

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PHP Error Message

Warning: is_dir() [function.is-dir]: open_basedir restriction in effect. File(/) is not within the allowed path(s): (/home/:/usr/lib/php:/tmp) in /home/a5328586/public_html/wp-includes/functions.php on line 2060

The above error is occurring after installing the event Manager plugin update.

the section of code referenced by the error is listed below {this function seems to be the one called to create new directories)

function wp_mkdir_p( $target ) {
	// from php.net/mkdir user contributed notes
	$target = str_replace( '//','/',$target );

	// safe mode fails with a trailing slash under certain PHP versions.
	$target = rtrim($target, '/'); // Use rtrim() instead of untrailingslashit to avoid formatting.php dependency.
	if ( empty($target) )
		$target = '/';  //this is line 2051

	if ( file_exists( $target ) )
		return @is_dir( $target );

	// Attempting to create the directory may clutter up our display.
	if ( @mkdir( $target ) ) {
		$stat = @stat( dirname( $target ) );
		$dir_perms = $stat['mode'] & 0007777;  // Get the permission bits.
		@chmod( $target, $dir_perms );
		return true;
	} elseif ( is_dir( dirname( $target ) ) ) { //this is line 2060
			return false;
	}

	// If the above failed, attempt to create the parent node, then try again.
	if ( ( $target != '/' ) && ( wp_mkdir_p( dirname( $target ) ) ) )
		return wp_mkdir_p( $target );

	return false;
}

I have spoken to the plugin creator and he blames the hosting company (cannot change hosting now) but I am not having any such issues with previous version of the plugin nor with other plugins

not sure if its also affected by the theme (arjuna)

but i am asking for help to modify the code here or in the plugin to resolve this.

help please