Devart.Data.Oracle.OracleConnection cannot be cast to... when running on server

i'm developing in vs2012 with oracle database and Entity Framework 6.0, using Devart.Data.Oracle to connect to database.in the last deploy i get this error,"Devart.Data.Oracle.OracleConnection cannot be cast to..." only when running on server. on the local machine + debuging mode, everything go OK.

i gess its relatate to Devart or Entityframework upgrade, and maybe related to the app.config file. but All attempts have failed.the full error message:Batch Console : [A]Devart.Data.Oracle.OracleConnection cannot be cast to [B]Devart.Data.Oracle.OracleConnection. Type A originates \from 'Devart.Data.Oracle, Version=8.1.36.0, Culture=neutral, PublicKeyToken=09af7300eec23701' in the context 'Default' at location \'C:\Windows\assembly\GAC_MSIL\Devart.Data.Oracle\8.1.36.0__09af7300eec23701\Devart.Data.Oracle.dll'. Type B originates from 'Devart\.Data.Oracle, Version=9.7.770.0, Culture=neutral, PublicKeyToken=09af7300eec23701' in the context 'Default' at location '\vsrvmink\un\VMIKUN\mikunjr\PVN\ctm01_mushlach_yomi\test\Status_Tst\Devart.Data.Oracle.dll'.

the config file looks like this:

<?xml version="1.0" encoding="utf-8"?><configuration><configSections><sectionGroup name="userSettings" type="System.Configuration.UserSettingsGroup, System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"><section name="ParallelRun.Properties.Settings" type="System.Configuration.ClientSettingsSection, System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" allowExeDefinition="MachineToLocalUser" requirePermission="false"/></sectionGroup><section name="entityFramework" type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=6.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false" /><sectionGroup name="applicationSettings" type="System.Configuration.ApplicationSettingsGroup, System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"><section name="ParallelRun.Properties.Settings" type="System.Configuration.ClientSettingsSection, System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false" /></sectionGroup></configSections><connectionStrings>   <add name="PVNEntitiesConnectionString" connectionString="metadata=res://*/DataModelContex.csdl|res://*/DataModelContex.ssdl|res://*/DataModelContex.msl;provider=Devart.Data.Oracle;provider connection string=&quot;User Id=pvn;Password=pvn;Server=test;Direct=True;Sid=test;Persist Security Info=True&quot;" providerName="System.Data.EntityClient"/><userSettings>      <ParallelRun.Properties.Settings><setting name="DeleteBeforeRun" serializeAs="String"><value>delete from pvn_tnuot</value></setting><setting name="DeleteBeforeDS" serializeAs="String"><value /></setting><setting name="ExportCommand" serializeAs="String"><value /></setting></ParallelRun.Properties.Settings></userSettings><system.data><DbProviderFactories><!--<remove invariant="Devart.Data.Oracle"/><add name="dotConnect for Oracle" invariant="Devart.Data.Oracle" description="Devart dotConnect for Oracle" type="Devart.Data.Oracle.OracleProviderFactory, Devart.Data.Oracle, Version=9.7.770.0, Culture=neutral, PublicKeyToken=09af7300eec23701"/>--></DbProviderFactories></system.data><entityFramework><providers><provider invariantName="Devart.Data.Oracle" type="Devart.Data.Oracle.Entity.OracleEntityProviderServices, Devart.Data.Oracle.Entity.EF6, Version=9.7.770.0, Culture=neutral, PublicKeyToken=09af7300eec23701" /></providers></entityFramework><startup><supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5"/></startup><applicationSettings><ParallelRun.Properties.Settings><setting name="LogFileName" serializeAs="String"><value>BatchLogTs</value></setting></ParallelRun.Properties.Settings></applicationSettings></configuration>

the first line code openning connection to database is very simple:int bankscounter = DataAccess.Instance.CountBanks();at this point all the connection components are loaded, and i get this error.any help/sעggestions are welkome.