This sounds like it is related to the HTTPS Certificate Issue. First, verify that DEP, and UAC are disabled. Also, verify you have the following patches applied

For Full installs:

1. Patch 1 Critical Update LR_03129
2. LR service pack 1 LR_03130
3. MS Cert patch LR_03159 (details below)

OR for standalone Vugen:

1. Patch1 Critical Update LRVUG_00029
2. LR Service Pack 1 (LR11.51) LRVUG_00030
3. Patch MS cert LRVUG_00044 (details below)

There is new Critical patch which fixes the HTTPs ''cannot display this page'' issue. HP released new patches for LoadRunner 11 and 11.5 to fix ''HTTPS'' issue. The problem is due to ''Microsoft Security Update KB 2661254'' (Microsoft Security Advisory: Update for minimum certificate key length) now requiring 1024 bit RSA Certificates and LoadRunner Vugen currently uses 512 bit RSA Certificates.

To comply with Microsoft security update http://support.microsoft.com/kb/2661254 the LoadRunner certificates shorter than 1024 bits have been replaced with ones that are 1024 bits .

For LR11.5x

* Full install Critical Update due to MS update --- LR 11.5x---LR_03159
or

* Vugen SA Critical Update due to MS update --- LR 11.5x--- LRVUG_00044

Available form HP