Cannot upgrade from JTS 3.0.1.2 to 3.0.1.3

Hi,

I tried to upgrade JTS 3.0.1.2 to 3.0.1.3 but I failed. I have followed the stept form this page:
http://publib.boulder.ibm.com/infocenter/clmhelp/v3r0m1/index.jsp?topic=/com.ibm.jazz.install.doc/topics/c_upgrade_clm_overview.html

I have tried to execute the jts_upgrade script but it fails. I have tried first:
C:\Pgm\IBM\JTS3_0_1_3\server>upgrade\jts_upgrade.bat -oldJTSHome C:\Pgm\IBM\JTS3_0_1_2\server\conf
... and I get the following message:
"Checking the old JTS version...
CRJAZ2124E The old JTS version could not be determined. Verify that the oldJTSHome is pointed at the correct installation and specify the version using the old JTSVersion parameter."

THIS is weird, as I have 3.0.1.2 and running repotools-jts -version in that old directory tells me exactly the same.

Then I tried the following command:
C:\Pgm\IBM\JTS3_0_1_3\server>upgrade\jts_upgrade.bat -oldJTSHome C:\Pgm\IBM\JTS3_0_1_2\server\conf -oldJTSVersion 3.0.1.2
... but now I get a different message:
"CRJAZ2122E The old JTS version must be a valid 3.x JTS version such as 3.0 or 3.0.1."

What should I do?

Kind regards,
Dacian