update the host file entries and also disable the firewall temporarily. redeploy the crystalreportviewer app in weblogic. Hope you have checked the functioning of report in other web application (try with tomcat 6 / 7).
additionally, please let us know whether you are using 4.1 SP1 / SP2 along with weblogic 10.3.6. One of our SCN colleagues had a similar problem. If yes, raise this to support. Issue can possibly be related with weblogic version compatibility with bi 4.1
GOOD LUCK!!