There is currently an issue with the reports where if you change the paper size or margins, when running the report ActiveReports tries to look at the default printer to make sure it supports those settings. This means that if the computer where the report is run does not have a printer installed you'll get that error. The only workaround is to try to install a printer driver on that machine. Or not change the settings of the report.
This issue will be fixed in the next release so that a printer won't need to be installed.
Dan Suceava
http://www.axosoft.com