using SugarPro v5.2d on a Linux server

Issue: when editing a contact that is not linked to an account - upon save, the account name field remains blank. I've tried linking to different accounts without success. When viewing the contact in the contact listview the contact is displayed multiple times (linked to the different accounts I have tried to link to). There is however only one instance of the contact in the database.

I have repaired database and rebuilt relationships with no luck.

I can link a contact to an account that has been manually created. The contacts where this is a problem were imported from a csv file. Possibly relevent is the import which did not link the records to accounts.

I've checked file permissions and changed all files to 664. the config.php was previously set to create files with 660 (octal 432). This has now been set to create 664 (octal 436).

Has anyone any suggestions/ideas?

Thanks

Marky