I have this problem too.
There are other threads in this forum about this issue, no solution yet (other than editing all templates).
It appears to only occur on windows machines, and doesn't really break anything. If you are just testing, I wouldn't worry about it... if you are developing then its really only a big issue if you are deploying on windows... on linux it seems to just go away. :)
Sorry taken me so long to reply but the solution is..
• This is due to a PHP bug
• The current version of PHP we are using has problems executing the sprintf function (sometimes)
• To fix this problem we need to remove the sprintf code from the ecommerce pages
Located in the ecommerce/templates/layout folder and the ecommerce/templates/includes folder.