The unrecognized attribute requestValidationMode error refers to an attribute and value (requestValidationMode="2.0") that is automatically added to the <httpRuntime . . . . /> node of the site's web.config when it is running in an ASP.Net 4.0 or 4.5 application pool. I am guessing that when you installed DotNetNuke locally and developed the site you were running ASP.Net 4.0 but now your hosted site's application pool is running ASP.Net 2.0/3.5. Other web.config modifications would also have been made for running under ASP.Net 4.0.

Note that while DotNetNuke v 6.2.5 and earlier will run under ASP.Net 3.5 SP1, DNN 7.x requires ASP.Net 4.0 or 4.5 application pool configured for integrated pipeline mode. You may have to have your hosting provider's support switch the application pool to ASP.Net 4.0/4.5 or you may be able to do so yourself in your hosting control panel.

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Bill, WESNet Designs
Team Lead - DotNetNuke Gallery Module Project (Not Actively Being Developed)
Extensions Forge Projects . . .
Current: UserExport, ContentDeJour, ePrayer, DNN NewsTicker, By Invitation
Coming Soon: FRBO-For Rent By Owner

If the connection strings that you posted earlier are still the ones in use then you have TWO active connection strings in both the <connectionStrings> section and in the <appSettings> section. The first connection string which referrs to SQL Express in each section should be commented out by extending the end of comment marker ("-->") or be removing the connection string completely. Below I show what "should" be the correct connection strings based on your earlier post with those related to SQL Express removed:

<connectionStrings>
       <!-- Connection String for SQL Server 2008/2012 -->
       <add name="SiteSqlServer" connectionString="Server=allium.arvixe.com;Database=DotNetNuke3;uid=www.XXXX.hr_dploy;pwd=PASSWORD;" 
              providerName="System.Data.SqlClient" />
</connectionStrings>
<appSettings>
       <!-- Connection String for SQL Server 2008/2012 - kept for backwards compatability - legacy modules -->
       <add key="SiteSqlServer" value="Server=allium.arvixe.com;Database=DotNetNuke3;uid=www.XXX.hr_dploy;pwd=PASSWORD;"/>

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Bill, WESNet Designs
Team Lead - DotNetNuke Gallery Module Project (Not Actively Being Developed)
Extensions Forge Projects . . .
Current: UserExport, ContentDeJour, ePrayer, DNN NewsTicker, By Invitation
Coming Soon: FRBO-For Rent By Owner