Indesign CS clipping mask problem

[ChromeZephyr]

Okay, apologies if this has been asked before...

I'm trying to RIP an Indesign CS file with a linked photoshop .eps file, clipped in Photoshop, with a drop shadow created in Indesign. Looks right on screen, but when I send the file to our RIP, there is a white square behind the image in the document. I've also tried clipping the file with Indesign's 'Detect Photoshop Path' feature, as well, but get the same result. I've rasterized the file to see if it's something wrong with the clipping paths, but it shows up correctly when rasterized.

Am I missing something here? Or could this be a problem between Indesign and the RIP software?