Hi cephids,
You can try the following regarding the InternetOpenFailedUrl error. If you want to manually download files you will find link for some installations on the license acceptance screen. If there are there others you wish to download please specify the program name.
In the following directory you will find the webpi.txt log files for each webpi attempt.
%USERPROFILE%\Local Settings\Application Data\Microsoft\Web Platform Installer\logs\webpi
Open the most recent file and look for the InternetOpenUrlFailed error.
Above this error you should find the URL that webpi failed to connect to. Test this url in IE manually. If this also fails then check the following article for troubleshooting connectivity with IE.
http://support.microsoft.com/kb/936211
If this works in IE but WebPi continues to fail Are you connecting via a Proxy Server ?
If so you can setup the proxy settings via config file called "webplatforminstaller.exe.config" and placing it here : C:\Program Files\Microsoft\Web Platform Installer\
In the Config you can try either of the following config settings.
<?xml version="1.0" encoding="utf-8" ?>
<configuration>
<system.net>
<defaultProxy enabled="True" useDefaultCredentials="True"/>
</system.net>
</configuration>
<?xml version="1.0" encoding="utf-8" ?>
<configuration>
<system.net>
<defaultProxy>
<proxy
proxyaddress="http://yourproxy.company.com:80"
usesystemdefault="True"
autoDetect="False" />
</defaultProxy>
</system.net>
</configuration>
Please let us know if this helps.
Thanks
Richard