Error after changed database from MSSQL to MySql

Hi,
I've changed the database of my nopCommerce installation from SQL Server to MySql. Now when application starts I get this error from SevenSpikes

NullReferenceException: Object reference not set to an instance of an object.
SevenSpikes.Nop.Framework.Plugin.BasePlugin7Spikes.SetupPermissionRecords()

TargetInvocationException: Exception has been thrown by the target of an invocation.
System.RuntimeTypeHandle.CreateInstance(RuntimeType type, bool publicOnly, bool wrapExceptions, ref bool canBeCached, ref RuntimeMethodHandleInternal ctor, ref bool hasNoDefaultCtor)

NullReferenceException: Object reference not set to an instance of an object.
SevenSpikes.Nop.Framework.Plugin.BasePlugin7Spikes.SetupPermissionRecords()
SevenSpikes.Nop.Plugins.Core.Infrastructure.RouteProvider.RegeneratePluginPermissions()
SevenSpikes.Nop.Plugins.Core.Infrastructure.RouteProvider..ctor()