Moved Servers - log4net could not be loaded error

Question

My code programmatically creates crystal reports.
Everything was working fine until we moved servers (unfortunately don’t have access to the old server anymore)
Get the dreaded error about log4net 1.2.10 that could not be loaded.  (Other assemblies in my solution rely on 1.2.11, so can’t just take it out)
I installed (repeatedly uninstalling the other and restarting the server)  the CRforVS_clickonce_13_0_9 32bit and 64 bit versions.
My application pool is set to allow 32bit applications.
I checked an do have log4net 1.2.10 in the GAC
Really out of things to try here and need fix this urgently for a demo to important client tomorrow (it’s midnight..make it today!)
For what it matter:
Development Machine (all fine here)
Windows 7, 64 bit
Visual Studio 2012
Crystal Reports 2012
Production Machine
Windows Server 2008, 64 bit
Full error (but guess you know it well)
Could not load file or assembly 'log4net, Version=1.2.10.0, Culture=neutral, PublicKeyToken=692fbea5521e1304' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)

Answer 1

btw, I moved 2 servers.  different projects but same technologies / tools.
Installed CRforVS_redist_install_64bit_13_0_8 on the one....works fine when creating reports and return as pdf.
On the other server....nope.  (the one I spoke about in original post)
For whatever it matter, here's the code I use (but doubt relevant since it worked just fine before)
var report = new ReportClass { FileName = reportPath };
report.Load();
report.SetDatabaseLogon(user, password, server, database);
var parameterValue = new ParameterDiscreteValue { Value = claim.Id };
var parameter = new ParameterValues { parameterValue };
report.DataDefinition.ParameterFields["@claimId"].ApplyCurrentValues(parameter);
report.ExportToDisk(ExportFormatType.PortableDocFormat, path);