The XLANGsCompiler.dll is installed with BizTalk Server 2010. It contains both managed and native code. This dll is not strongly named in this release of BizTalk Server, because strong naming results in more managed code being run, which increases the chances of a deadlock due to the following CLR issue: http://msdn.microsoft.com/en-us/library/aa290048.aspx#vcconmixeddllloadingproblemanchor7.