I receive an error when Magento stock is synced from outside source

My Magento store receives stock status from a scrapper source but when sync process is executed it stops before finishing the syncing, and I receive following php error in log.

[06-May-2015 18:00:58] PHP Fatal error: Uncaught exception 'PDOException' with message 'SQLSTATE[HY000]: General error: 1205 Lock wait timeout exceeded; try restarting transaction' in /home1/darrosme/public_html/store/lib/Zend/Db/Statement/Pdo.php:228 Stack trace:

0 /home1/darrosme/public_html/store/lib/Zend/Db/Statement/Pdo.php(228): PDOStatement->execute(Array)

1 /home1/darrosme/public_html/store/lib/Varien/Db/Statement/Pdo/Mysql.php(110): Zend_Db_Statement_Pdo->_execute(Array)

2 /home1/darrosme/public_html/store/app/code/core/Zend/Db/Statement.php(291): Varien_Db_Statement_Pdo_Mysql->_execute(Array)

3 /home1/darrosme/public_html/store/lib/Zend/Db/Adapter/Abstract.php(480): Zend_Db_Statement->execute(Array)

4 /home1/darrosme/public_html/store/lib/Zend/Db/Adapter/Pdo/Abstract.php(238): Zend_Db_Adapter_Abstract->query('UPDATE `catalog...', Array)

5 /home1/darrosme/public_html/store/lib/Varien/Db/Adapter/Pdo/Mysql.php(428): Zend_Db_Adapter_Pdo_Abstract->query('UPDATE `catalog...', Array)

6 /home1/darrosme/public_html/store/lib/Zend/Db/Adapter in /home1/darrosme/public_html/store/lib/Zend/Db/Statement/Pdo.php on line 234