gnucash-2.2.7 doesn't (IMHO) log enough (any?) information about failures to load optional modules. It was a bit of work to debug a recent problem (564033) and I ended up tweaking gnc_module_load_common() a bit to coax the error messages out. I slightly reorganized the code in this function to accomplish two things:

1. Make the logic clearer to someone new to the code (i.e., me)
2. If an optional module is found, log any errors in loading it

I tried to maintain the original spirit of not squawking too much about unfound optional modules while still generating messages about legitimate problems. I think it would be a useful change for others; hope you agree!

There doesn't seem to be a way of uploading a patch with this bug report, so I have put it here: http://www.sonic.net/~enrico/patches/gnucash-2.2.7/patch-src-gnc-module-gnc-module.c