Problem with installing OpenMx on R 2.13

> require(OpenMx)
Loading required package: OpenMx
Error in dyn.load(file, DLLpath = DLLpath, ...) :
unable to load shared object '/Library/Frameworks/R.framework/Versions/2.13/Resources/library/OpenMx/libs/x86_64/OpenMx.so':
dlopen(/Library/Frameworks/R.framework/Versions/2.13/Resources/library/OpenMx/libs/x86_64/OpenMx.so, 6): no suitable image found. Did find:
/Library/Frameworks/R.framework/Versions/2.13/Resources/library/OpenMx/libs/x86_64/OpenMx.so: unknown required load command 0x80000022

My R version is as follows:
R.Version()
$platform
[1] "i386-apple-darwin9.8.0"

$arch
[1] "i386"

$os
[1] "darwin9.8.0"

$system
[1] "i386, darwin9.8.0"

$status
[1] ""

$major
[1] "2"

$minor
[1] "13.1"

$year
[1] "2011"

$month
[1] "07"

$day
[1] "08"

$`svn rev`
[1] "56322"

$language
[1] "R"

$version.string
[1] "R version 2.13.1 (2011-07-08)"

Does anyone know how to deal with this problem?