Converting a program to arcgis 2010

[AnatoliiTerentiev]

Dear Gurus!
I wrote previous program on c#  under vs 2005, using arcgis Engine 9.3.
Now I have 64-bit - computer and work on vs 2010 with arcengine 10.0.
I have convert program from vs 2005 to vs 2010 and from arcgis 2010 to vs 2010
with standart instruments. But now when running program , I have error message:

Error 1 unload "file:///C:/Program Files (x86)/ArcGIS/DeveloperKit10.0/DotNet/ESRI.ArcGIS.ADF.dll" or one of dependent components because of wrong format

. Error was on next string -

  <data name="axToolbarControl1.OcxState" mimetype="application/x-microsoft.net.object.binary.base64">
    <value>
        AAEAAAD/////AQAAAAAAAAAMAgAAA...
</value>
  </data>

The original version was in 32-bit computer , and target platform - x86, and target framework - .Net framework 2.0.
In converted version I leave the previous settings.
May anybody help to solve problem?
Thanks in advance!
PS. On 32-bit computer the program after converting  work normally.

[RichardWatson]

Set the project to build x86.  You can't build a 64 bit (or AnyCPU) executable image which references ESRI assemblies (which are 32 bit only).

[AnatoliiTerentiev]

Thank you very much!
And what about target framework? Can it be 2.0, when I use arcobjects 2010? Or must be target framework 4.0?

[RichardWatson]

ESRI does not support the 4.0 framework until 10.1 and then only optionally.

3.5 is the one you seek.