Since the language packs are getting larger, the command timeout to import them into the database should be increased from the default of 30 seconds. This will reduce the likelihood of getting the following error message (and corresponding SqlException) when importing a language pack: "Timeout expired. The timeout period elapsed prior to completion of the operation or the server is not responding.".
File: Libraries\Nop.DataAccess.SqlServer\Localization\SQLLocaleStringResourceProvider.cs (insert the following at line #213 in method InsertAllLocaleStringResourcesFromXML()).
dbCommand.CommandTimeout = 300; // Allows five minutes for the import
as far as I know, when I import a Language Pack file locally on my laptop it last arround 2 minutes. The code is designed to TimeOut after 5 minutes (600 sec).
See that in the file : Nop.BusinessLogic/Localization/LocaleStringResourceManager.cs
I still have the same problem ... timeout ... french language pack for 1.90 version running on Arvixe servers, therefore remote ... thinking of going the XML import directly into the database ...