You may try downloading the latest drivers from logitech - there are two versions the blue backlight and red backlight.
Download the current drivers (I just confirmed they are the same file names for both versions).
Uninstall the old drivers, reboot, and load the new drivers.
I downloaded the new version (only found one version lops304b_x64.exe) and replaced the older lgps_304_x64.exe version. It did seem to help the problem coming out of sleep but I am now seeing some console (or windows interface) errors from several Microsoft programs (like the VS2008) that cause the programs to abort with an apparent memory error. These events seem to only occur after the machine has been in sleep and seem to be fixed (until after some subsequent sleep) by a system restart. This behavior appeared after the new driver was installed so I suspect the new driver. Suggestions?
When you uninstall the Logitech drivers, does the error cease? Have you contacted Logitech support to see if they know about the error? They may have a fix, or a workaround. With the prices of their keyboards, they want them to work with Win7.
I tried uninstalling the G15 keyboard drivers. Problems go away but so does the added functionality so it seems to be a driver problem. Looking over the internet, I noticed many complaints about the G series keyboards with Windows 7.
Based on all this, I put the G15 in the closet and got a Microsoft Sidewinder X6 (the one that says Windows 7 certified on the box. Everything works, no problems!