Using Delphi 7, I wonder if there is a free component which will collect diagnostic information as my application runs at a remote site and will help me to debug error reports.<
Have you looked at the open-source JclDebug from Project Jedi? Here's a nice succinct write-up on JclDebug.
Imagine you could get a detailed error-report containing a full callstack of where the error occured combined with information about file and line-number. This report could be generated directly on the users computer and be sent to you via email or directly via the internet, using a custom procedure - even directly creating entries in the bugtracking-tool you are using.
This and more is made possible by the Project JEDI - more accuratly, the JCL-Subproject with its JclDebug-Framework. When you have completed the installation of the package, a new Menu Option called "Inser JCL Debug Data" will be added to the Project-Menu of your Delphi-IDE.