The ECMT manager which forms part of the S60 MIDP SDK doesn't work out of the box with Java 1.6 (6.0). In this situation the error 'Cannot start ECMT Manager' is displayed when attempting to open the manager.

To fix this do the following:

•  Navigate to <S60 MIDP SDK Install Path>\bin\epoc32\tools\ecmt\config
• Backup (via copy) config.properties to config.properties.original
  
• Open config.properties in a text editor
• Locate the property epdt.java.version.start and append the String ',1.6,6.0' (excluding the quotes) to it's value
  e.g. epdt.java.version.start=1.4.1,1.4.2,1.5,5.0,1.6,6.0
• Save the file.

Now try and open the ECMT manager again, if the fix has worked then the manager should open without any errors occuring.

Hope that helps,

EdD