ECC 6.0 EhP6 SPS08 failed with RC12 in phase ACT_UPG

Dear gurus,

We are upgrading from ECC 6.0 EHP4 SP12 to ECC 6.0 EHP6 SP8 and phase ACT_UPG has failed with RC12. When we check the dump it shows the following error:

Runtime error: DBIF_REPO_SQL_ERROR

Shorttext:  SQL error "-99999" occurred when accessing program

Database error text........: "CLI0106E Connection is closed. SQLSTATE=08003"

Triggering SQL statement...: "CX_SY_OPEN_SQL_DB=============CP "

Internal call code.........: "[REPO/*/43/LOAD/CX_SY_OPEN_SQL_DB=============CP

]"

Any help would be appreciated

Thanks

Diana