macOS dlopen() won't load my dylib, help!

I'm a OSX newbie so please be kind. dlopen() won't load a dylib, dlerror() returns:

Unable to load /path/to/my.dylib. dlopen(/path/to/my.dylib) failed: dlopen(/path/to/my.dylib): no suitable image found. Did find: /path/to/my.dylib: unknown file type, first eight bytes: 0x21 0x3c 0x61 0x72 0x63 0x68 0x3E 0x0A

I believe this means something is wrong with my dylib, but I don't know what. I also tried creating the lib as a bundle by changing the project values shown below, but I still get the same error:

MACH_O_TYPE mh_bundle
LIBRARY_STYLE BUNDLE

Please point me in the right direction. We need to load the lib at runtime because we will load a different lib depending on runtime parameters and we try to use dlopen() to keep code identical across platforms (Solaris, Trusted Solaris, Linux, OSX) but replacing dlopen() with a different function call will be fine in this case as long as we can load the lib at runtime. Please help!

Thank you very much for your replies, I'll try to answer your questions:

(1) Yes all of my binaries are compiled for the same architecture (main executable and libraries). I created the project by copying a working "dynamic library" target, then changing the source files and changed the output type (Mach-O type) to bundle. The call to dlopen() to load this lib happens inside the dynamic library, is that itself a problem?

(2) Output of file /path/to/my.dylib: my.dylib: current ar archive random library

I'm not sure why this doesn't say "Mach-O bundle i386" because my project is set to output a "bundle". Maybe changing the Mach-O type alone isn't enough?

(3) I'm using xcode 3.2.1 x86, base SDK 10.5, gcc 4.2, deployment target OSX 10.5, dynamic link to libstdc++, Mach-O Type Bundle,

(4) To create the project I right clicked a working target of type dynamic library and selected "Duplicate", then I changed the source files, output name and Mach-O type to "bundle".

(5) Project options are as shown above, but let me know if you would like anything additional.

I will try starting a new project of type bundle, though I'm still not sure why this one isn't working..

I've figured out the problem. Even though I changed the setting in xcode to specify output type "dynamic library" or "bundle", xcode was ignoring the setting. Starting a new BSD dynamic library project solved the issues I was seeing. Thanks for the help!