This error means that bridge.php cannot write to temporary directory specified. By default temporary directory detected automatically and this autodetect works in 9 of 10 situations. If for some reason autodetected temporary directory does not work (access denied or so) you can set it manually.

Edit bridge.php file. There's a line:

//$temporary_dir = "./tmp"; // on some systems if you get output with 0 size, try to use some local temporary folder

1. uncomment this line - remove two slashes at the beginning
2. connect to your store via FTP and upload modified file there - all other actions should be made on your store server
3. create directory "tmp" in the same folder where bridge.php placed and assign write access rights for all groups

Try to make some changes using Store Manager through bridge, if everything was set properly it should work well.