Since you have a 64 bit system, you will need to check and apply this kb: https://support.laserfiche.com/KB/1012684 

The original error is 0x800700b7 which the KB does not reference. The second problem after "resolving" the first error does not list any error codes. 

In the KB it says to check scenario 6 in order to accomplish the following: See Scenario 6 for details on workarounds to either disable the XPress compression scheme, configure IIS to only load the 64-bit version of the module for 64-bit application pools, or to use a 32-bit version of the compression module.

The Xpress compression scheme is not installed. The IIS app pool is set to integrated and 64 bit(32bit apps are not enabled). The compression module file "suscomp.dll"does not exist on the system in either 32bit or 64bit form. It also talks about adding preconditions to module entries which I am not sure which modules to apply them to.

For the 800700b7 issue, please review this MS article: http://support2.microsoft.com/kb/942055

I feel as I might not be explaining the situation correctly.

I tried to access the "http://<servername>/weblink8/" link, I received an HTTP error 500.19 - 0x800700b7 in Internet Explorer.

The error points to a duplicate instance of "<add value="Welcome.aspx" />". This is being set elsewhere in IIS so the entry which is located in the web.config for Weblink is unnecessary. See screen shot in the intial post.

I edited the web.config in the "C:\Program Files\Laserfiche\WebLink 8\Web Files" folder. I commented out the line "<add value="Welcome.aspx" />" which is located under <defaultDocument>.

I saved the changes to the web.config file.

After making the changes I tried loading the "http://<servername>/weblink8/" page again. Now I receive "Object reference not set to an instance of an object" error when trying to load the page(see screen shot in initial post). Trying to access "http://<servername>/weblink8/login.aspx" or "http://<servername>/weblink8/welcome.aspx" results in the same error.

I also attached a copy of the Windows Event Viewer entry created when the page tries to load(event_viewer_entry.txt).

I tried some of the fixes provided by "https://support.laserfiche.com/KB/1012684" with no change in behavior. Those fixes seem to be for a different problem all together.

To make sure it is not something as simple as a corrupted Welcome.aspx page, please uninstall Weblink, delete the Weblink installation directory and reinstall it.

I will schedule downtime and try this. I forgot to mention this is Weblink 8.2.2

I was able to re-install Weblink 8.2.2 during a maintenance window last night. I am experiencing the same problems with the new install.

Did you modify the config file and remove the <add value=> entry
as suggested by the MS kb http://support2.microsoft.com/kb/942055? 

Yes, I made the same configuration changes as my prior post as I had received the same errors.

Please open a case with Support.

Case 163206 opened. Thank you for your time.