Fix to :

http://issues.umbraco.org/issue/U4-5475
http://our.umbraco.org/forum/getting-started/installing-umbraco/56540-Could-not-install-packages
http://our.umbraco.org/forum/getting-started/installing-umbraco/57035-Installing-Package-Error-invalid-search
http://issues.umbraco.org/issue/U4-5571

Ecc...

This is only  a temporary workaround, because this is a stupid way of parsing a URI!!
1) It's not a real parsing, it uses browser DOM API with correlated compability problems (Invalid Protocol in Internet Explorer)
2) Check the validity of url clientside is useless...