What does "running without executing" mean? Do you mean it starts to execute and never finishes?
Some things to try...
- If there are multiple queries in your report, try running the tabular sql for each and see if that completes OK.
- If you're using a non-html output format, run it in html and see if that makes a difference.
- Copy the generated sql from your query/queries and run it in your database client.
The results will help determine if your problem is with the database retrieval, local processing, or output formatting.