When exporting the first thing CR does is try to write a file to the temp or destination folder to check if it has full read/write abilities. If it fails it means no R/W access or the system is not capable of keeping up.
The RDC was NEVER built to do report bursting and never will be. Only option is to add more delays.
Check your ProcessMonitor logs to see what is happening when they first try to export.
Don