Got OS 3.5 and 3.9.. but cannot install :/

[amigagr]

the standard process in both cds is to make first an Emergency floppy disk, then boot from this floopy with the cd in the drive, and after boot, run the normal instal from cd. did you made this Emergency floppy?
why you bought both? os3.5 is part of 0s3.9 cd.
just use the 3.9. make the floppy and go on. what brand is your turbocard? do you have any ide/scsi extra hardware connected on amiga? sometimes this bring some troubles.

-edit-
here you can find more usefull instructions

[amigagr]

maybe you accidendaly try to install to the cd drive? what is the name/volume of your hard disk boot partition?

[amigagr]

ok, try this: run a shell from the emergency disk and type:

makedir ram:t
assign t: ram:t

close the shell and run again the installer.
probably it's trying to find the t: (temporary) directory on the cd and gives you the error.

[amigagr]

in the emergency disk in the directory system, it's a program called shell. click twise to run it. it will appear a dos prompt. in this prompt type

makedir ram:t
press enter
assign t: ram:t
press enter
endcli
press enter
and run the installer

[amigagr]

wrong answear!!!
you have the 3.0 rom
you need 3.1 to install os 3.5 or/and 3.9
.........................................

[amigagr]

amigakit rom3.1  the version of 3.1 rom is 40.68

[amigagr]

good luck :-)

[amigagr]

that's more than a lucky situation you know
bad for the old a1200... i have 2 in a similar condition from friends, but they have the 3.0 rom both!!!