I had a similar issue recently. I remoted into the machine and ran the psexec command that the SSIS package was attempting to run and it worked fine. So I logged off of the machine and logged back in with the credentials used by SQL Server Agent (which is the same credentials the agent job was configured to use) and tried running the psexec command and to my surprise, a window pops with the license agreement and the program wouldn't execute until I clicked the accept button. After that, the scheduled SSIS package worked without issue. Basically, the 1st time you run any of the executables from sysinternals this window pops up and it isn't machine specific, but user specific. I'm sure there is probably a registry entry you could edit, but it's easy enough to login with the agent account credentials or runas the agent account credentials to get this squared away.