Unable to validate AIR installation

Hi, we are using native installer feature on both WIN and MAC os. On computers, that do not have AIR runtime already installed, the installation fails with the message: "Unable to validate the downloaded version of Adobe AIR Please install the latest version of Adobe AIR from..."

This is happening on all the computers, we are able to test it on both WIN and MAC, so I assume this is a general problem, not related to single machine.

Downloading and installing the runtime separately from http://www.adobe.com/go/getair succeeds and so do the installation of our applications afterwards. But this is not acceptable workflow for our clients. Here is a part of the installation log from my computer running Windows 7 64bit.

[2012-10-09:09:18:51] Bootstrapper begin with version 3.4.0.2540 on Win x86

[2012-10-09:09:18:51] No installed runtime detected

[2012-10-09:09:18:51] Begin runtime download from http://airdownload.adobe.com/air/3/nai/windows6.1/x86/installer

[2012-10-09:09:18:56] Download success

[2012-10-09:09:18:56] Begin signature download from http://airdownload.adobe.com/air/3/nai/windows6.1/x86/installer.p7

[2012-10-09:09:18:56] Download success

[2012-10-09:09:18:56] Detached signature validation failed

[2012-10-09:09:19:28] Download cancelled

[2012-10-09:09:19:28] Bootstrapper end with exit code 13

We have tried packaging against AIR 3.2.0.2070, AIR 3.4.0.2540 and the latest release from yesterday. I have also tried installing an older application build with AIR 2.6, which I am sure worked. Still the same problem..

Any help or comments would be highly appreciated. Thank you in advance.