Not "Global Assembly", but "Global Assembly Cache", GAC. Please formulate your questions accurately, copy/paste real error messages or exception information. The assemblies do not appear in GAC by themselves. :-)
It looks like you need to make Crystal Report redistributable installation a prerequisite for installation of your product.
Please see the main page of SAP Crystal Reports:
http://www.sdn.sap.com/irj/boc/crystalreports-dotnet[
^].
On this page, locate "Redist Intallation (32 bit)" or "Redist Intallation (64 bit)" (closer to the end of the page):
http://downloads.businessobjects.com/akdlm/cr4vs2010/CRforVS_redist_install_32bit_13_0_2.zip[
^],
http://downloads.businessobjects.com/akdlm/cr4vs2010/CRforVS_redist_install_64bit_13_0_2.zip[
^].
This is what you should make your customer to install. You can redistribute required package with your product.
—SA