Wrong datatype & Bad arguments warnings from query.php

I have just installed wordpress on my test debian server to get to know the application. I have these errors at the top of the page, and don’t know how to resolve them.

Warning: in_array() [function.in-array]: Wrong datatype for second argument in /home/peatblog/public_html/wp-includes/query.php on line 2302

Warning: array_map() [function.array-map]: Argument #2 should be an array in /home/peatblog/public_html/wp-includes/query.php on line 2318

Warning: implode() [function.implode]: Bad arguments. in /home/peatblog/public_html/wp-includes/query.php on line 2318

The section in query.php that these errors refer to is this (I have indicated the lines the errors refer to):

// Put sticky posts at the top of the posts array

Line 2302:			for ( $i = 0; $i < $num_posts; $i++ ) {
				if ( in_array($this->posts[$i]->ID, 

			// Fetch sticky posts that weren't in the query results
			if ( !empty($sticky_posts) ) {
Line 2318:				$stickies__in = implode(',', array_map( 'absint', $sticky_posts ));

Has naybody come across these errors and know how to resolve them.

Thank you in advance.