After some trial and error i found that the following resolved most of the problems i was expeiencing
#Shutdown and restart instance in upgrade mode.
#now invalidate the existing packages
#As i have already patched the system to DST V10 i needed to do the following
#now i started to convert/upgrade the database, i started with the upgrade catalog
# as it resolve a lot of issues i experienced.
#Then the more standard catalog procs were applied.
#Finally, get all of the procs recompiled.
#then check for any outstanding issues
select * from sys_objects where Status != 'VALID';
Now i did have a few invalid objects but these are application specific and fairly easy to resolve.
I haven't experienced any more issues with the conversion. However, if there are any ommissions or other issues with this approach i will be glad to hear about it.