Thank you for your answer.
I am using Installshield Express 4.0 SP2.
A few notes on where I am at with this issue,
First I downloaded the CVIRTE installer (6.0) from ni's website and opened the msi in orca. It also contained the same custom action (literally the function its calling and everything is the same). Then I created a blank LabWindows project and created a distribution kit with install full rte selected (so it essentially just installs the rte) and this one also ran fine (in fact I am run this one in the background of my installer now). Again I opened the .msi file in Orca and the custom action is there, with the exact same settings as the downloaded and installshield version. Lastly I created a blank installshield project and the only
dependacey was cvirte.msm (and its dependacies such as nipaths.msm), again I opened the msi in Orca and the custom action is there as expected, but when you run the installer you recieve the error Internal Error 2721....
I am not exactly sure (thus the post) but it seems that for some reason the dll that contains the function _nmdkTouchFiles@4 (its close to that name) is not being pulled into the msi.
Question:
In what dll does this function reside? Is it a dll that I have access to? If so one possible solution would be to replace the custom action in orca with one created in the installer that would force the dll into the installers msi. Just a thought though this may not work but Im willing to try.
Thanks again for looking into this matter, I hope that I have provided you with all the information that you require.