First of all, remember that there were two versions of the Squirrel SCSI adapter made:
1. Surf Squirrel - which includes a serial port.
2. Squirrel - which does NOT include a serial port.
Make sure you have the correct install disk(s) for your adapter, you can find them by following this link:
http://amiga.resource.cx/exp/squirrelAnd remember - the CD0: icon information SHOULD look like this:
ACTIVATE=1
DEVICE=squirrelscsi.device
UNIT=3
FLAGS=1
With squirrelscsi.device as DEVICE - NOT cd.device, scsi.device or squirrel.device. The UNIT should also be set to 3 and not 0.
This is the CD0: icon information, but have you also looked at the actual mountlist? Just open CD0 in a text editor (like Ed), you can do this by entering the following in shell: Ed SYS:Devs/DOSDrivers/CD0
One important entry in this file is FILESYSTEM, make sure that the file mentioned here exists on your system (should be in Sys:L)