WordPress.com Stats plugin warning

I’m using the WordPress.com Stats (1.2.2) plugin, and it partly works: In the Dashboard, I get a warning message in the right hand half of the Stats panel, like this:

Warning: tmpfile() [function.tmpfile]: open_basedir restriction in effect. File(/tmp) is not within the allowed path(s): (/home/virtual/mydomain.com:/home/virtual/_tmp) in /home/virtual/mydomain.com/public_html/wp-content/plugins/stats/stats.php on line 613

Warning: tmpfile() [function.tmpfile]: open_basedir restriction in effect. File(/tmp) is not within the allowed path(s): (/home/virtual/mydomain.com:/home/virtual/_tmp) in /home/virtual/mydomain.com/public_html/wp-content/plugins/stats/stats.php on line 613

Warning: tmpfile() [function.tmpfile]: open_basedir restriction in effect. File(/tmp) is not within the allowed path(s): (/home/virtual/mydomain.com:/home/virtual/_tmp) in /home/virtual/mydomain.com/public_html/wp-content/plugins/stats/stats.php on line 613

I’m running WordPress 2.6, but I had the problem in 2.5 too. Any suggestions?