Exporting to Photoshop -- Error: DNG with RGB processing limitations

I use a Mac. I imported RAW images to Photo Mechanic to review and edited an image in PhotoLab. When it was exported back to Photo Mechanic it was exported as a DNG and a DNG remains in Photo Lab. I want to do some additional editing in Photoshop but get the error message:

Error: DNG with RGB processing limitations: The batch queue only contains RGB images but is set to output DNG files. Processing cannot continue.”

I don’t understand this and don’t know what to do. Can someone explain (in a bit of detail, please!). Thanks. Stephanie

The DNG exported by PL5 is a linear DNG and is already demosaiced. You will probably need to export a TIFF instead of a DNG.