We generate test reports with links to run one of our Hudson jobs using URLs like:

http://<hudson_server>/job/<job-name>/buildWithParameters?Var1=..%255Cqdirname&Var2=dirname%255Cimgname&Var3=filename&Var4=A+comment+here

This works perfectly if the user who clicks the link to run the job is already logged into Hudson, but if that person isn't logged in, they'll be redirected to the login page. Once they've logged in, the build starts, but the values that were passed in the URI are no longer accessible.

For example, if we have this in "Execute Shell":

echo "Calling: python run_job.py \"$Var1\" \"$Var2\" \"$Var3\" \"$Var4\""

We get this in the console output:

+ echo 'Calling: python run_job.py "" "" "" ""'
Calling: python run_job.py "" "" "" ""

Please let me know if I can provide any more relevant information.