Photoshop :: Blue Flower Prints Purple From PS CS3

I am using WinXP/Home, Adobe RGB 1998 Color profile for both the image and Photoshop CS3. I print on Epson R2400, have freshly and properly installed inks and nozzles are not clogged. I have an image of a blue flower, and I do mean blue, not purple and not lavender. It is definitely blue on the monitor. It is blue in Bridge. It is blue in its jpg format and in its .psd format. When I print using the printer with Photoshop as color manager and print management off, the result is a purple flower. All the other colors in the image seem to be fine---green is green, yellowish is yellowish. When I print using printer color management(settings all properly done), NOT Photoshop's, I end up with a blue flower! Anyone with any ideas at all why this happens? I sure would appreciate knowing! I can do the workaround by letting the printer manage color, but seems to me that Photoshop really ought to be doing this. I have not noted problems with any other colors...only blue!