Repost: CD Rom install problems with PMac Dos

[Van Bel Hubert <chalpa@ctv.es>]

Repost: (I received no answer) .

I have a 6100/66 PowerMac Dos comp. with 7.5.3 System installed.
Cause of some problems I had to reinstall the system software, including
Dos and Windows 3.1. 
But...
When I restart the Mac, I get a window that the following extentions
cannot be loaded:
High Sierra File Access
Iso 9660 File Access
Audio CD Access.
I disabled these extentions and loaded Rapid CD. With this Rapid CD
control Pannel I can read and play CDs. The Apple Audio CD player does
not work and mentions that the CD rom drivers are not correctly
installed.
Solutions ?
What is more important is that although I correctly installed the Dos +
Windows 3.1 + 1 discette called Soundblaster 16, I cannot read CD-roms
in the PC part. I think that before the CD-rom was in E. Now I don't
have E, only A, C and D.
Solutions ?
Best regards
Hubert Van Bel
Email: chalpa@ctv.es