The usual cause of the report program taking so long to generate a report is low conventional (base) memory. Free up as much base memory as possible and the speed of report generation will improve.

Assuming that you are using Quik Reports for DOS, this is also often caused by incorrect Links being used in the report. Decide which file should be driving the report. The Edit | Links and set the relationships from the driving to the other files used on the report. Normally, you will want to choose the driving file to be the one that has a one-to-one correspondance with the other files in the data. (If you tell me what information you are displaying on the report, I might be able to provide some assistance.)