Hi Srinu and welcome to the HP QC Community! Regarding the error you are encountering when you try to create a project by copying the date from an existing one, could you let us know what is the QC/ALM version that yo uare using and if this error is observed with more than one project? If only a single project is affected, then could you try below steps:
1. Backup your source project repository and database
2. Remove the project (do not delete it!) from ALM Site Administration
3. Restore the project by using the restore option and pointing to the project’s dbid.xml file (located in the projects' repository)
4. Try creating a new project by copying the date from this one.
Thanks,
Hristo