Hi TC, welcome.
I think the problem is actually OS/2 is getting confused about the drive letters. OS/2 ver 4 and older use the same hardwired drive lettering as DOS, 1st primary on HD0 is C:, 1st Primary on HD1 is D: etc. At some point during the boot, OS/2 gets confused, thinks that your IDE drive is HD0 and that is where C: is and can't find its device drivers starting with country.sys. If you removed it from config.sys, the next driver would fail to load.
I don't have experience with SCSI or mixed systems so not sure the best solution is. If you don't need to access the IDE drive, you could try remming out the BASEDEV=IBMS506.ADD line so that IDE drives aren't seen.
Better might be rearranging config.sys. Guessing, your SCSI drivers should come before IBMS506.ADD. You might want to post the relevant part of config.sys.
Others with more experience may have better ideas.
Don't delete stuff like country.sys in config.sys to attempt to fix.