Here's a test that you can do. If it works you can batch change all of the files and then import. The only downside to this is that it will apply one level of JPEG compression to the file. I don't find it to be detrimental to the quality or resolution of the image but your eyes are probably a lot younger than mine and may be more discerning.
1 - to to Toad's Cellar and download "http://oldtoad.net/ToadsCellar/downloads/ConverttoJPGandEmbedsRGBprofile.ziphttp://oldtoad.net/ToadsCellar/downloads/ConverttoJPGandEmbedsRGBprofile.zipConv ert to JPG and Embed sRGB profile.zip".
2 - unzip the package and put the app on the Desktop.
3 - Control (right) - click on the app and select Open for the first time - due to the sandbox feature of OS X.
4 - drag one image file onto the app for conversion.
5 - try importing the converted image file.
If the above works you can drag all of the photos onto the app for batch conversion. Be sure to run this on copies of the files as it will convert the original file and if it's not to your liking you can return to the original.
NOTE: The curent app puts the new files on the Desktop. Will have to edit it with Automator to create a new folder and put the newly converted files in it.