Product:
Cognos Tm1 version 9.5.1
Microsoft Windows 2008

Symptom:
During install with IBM Cognos TM1 Installation Wizard you get this message
Internal Error 27555, c:\inetpub\wwwroot\TM1Web\
The parameter is incorrect.
, 87

Problem:
Cognos TM1 does not support to be installed on Microsoft Windows Server 2008 standard. You must use Microsoft Windows 2008 R2.

Cognos TM1 version 9.5.1 support this
https://www-304.ibm.com/support/docview.wss?uid=swg27018895

Cognos BI 8.4.1 support this
https://www-304.ibm.com/support/docview.wss?uid=swg27017522#os

When you are going to integrate TM1 and Cognos BI you must install parts of TM1 on the BI server – therefore the Microsoft Windows OS must be supported by TM1 also.

Solution:
Install a new server with Microsoft Windows 2008 R2.