You do not need to install the Infragisitcs product line in the
production server - the only thing you need is the Infragistics product
assemblies. They should be placed in the top level /bin folder of your
web-site / web-project.
This can be achieved by selecting the
"Copy Local" option for each assembly reference - this will copy them
from the GAC (Global Assembly Cache - where the IG installer puts them
by default) to your /bin folder and you can simply copy paste the
entire website to the production server - this should address the
problems.
For example, if you are using the 8.1 version of
UltraWebGrid, you need to following assembly in your /bin folder (if
you are targetting ASP.NET 3.5):
Infragistics35.WebUI.UltraWebGrid.v8.1.dll