This is because macosx mono is 32-bit and this can't p/invoke 64-bit binaries.
However, the reverse is also true.
If OpenSimulator stops working for you then please complain! Long term alternative is probably to build a fat binary with both architectures.
This is because libopenjpeg 1.5 appears to require a minimum of glibc 2.14, whereas at least one fairly recent distro (openSUSE 11.4 from 2011-03-10) only has glibc
Further investigation pending.
Among other things this allows pCampbot to work under Windows since libopenmateverse now ships the same log4net.dll (publicly signed) as OpenSimulator
This also updates the libopenmetaverse embedded libopenjpeg from 1.3 to 1.5.
DLL naming and mapping for non-Windows libopenjpeg changes to remove version number to make future udpates easier and bring it into line with names of other shipped DLLs.
libopenjpeg updates have been made for OSX, Windows (32 and 64 bit) and Linux (32 and 64 bit). Please report any issues.
Justin Clark-Casey (justincc)