security update problem

[Tobias]

got a strange problem do a dapper normal server install, at the end it 
tells that can not get the security updates.
in the source.list it says then: #Line commented out by the installer 
because it failed to verify:
when i uncomment the security deb... lines apt-get update still has 
error messages.

got a dapper pc there apt-get update has no problem, on the same archive.
only on the new server installation it makes it, made a new 
installation, again same error messages.
network works fine.

any help on this, never seen such a thing