MySQL: Error 1016 when using LOCK TABLES

I run a nightly mysqldump of all my databases and one of them has over 500 tables, mysqldumper bring me a error while processing this huge database:

My Error message:

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mysqldump: Got error: 1016: Can't open file: './dbname/tablename.frm' (errno: 24) when using LOCK TABLES

I found two different solutions to avoid this nasty problem.

Solution one:
This solution will cause mysql to keep only one table open at a time.
Little example of the mysqldump command:

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mysqldump --single-transaction --user=root --password=root database >database.sql

Solution two:
The second solution is a little bit dirty, it will skip all locked tables.
Append –skip-lock-tables option to your mysqldump operations, this will look like this one:

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mysqldump --skip-lock-tables --user=root --password=root database >database.sql