Solution : https://service.sap.com/sap/support/notes/515957 (SAP Service marketplace login required)
Key words : 
symptom activation errors occur, import support packages sapkh31ia1, <sid> activation log, support package manager, support package sapkh31ia3, support package sapkh40b75, /3 support package sapkh46b41, /3 support package sapkh46c33, support packages imported, including support packages
Related Notes : 
       
| 390062 | Additional information about upgrading to 4.6C SR2 | 
| 327285 | Additions to upgrade to 4.6C SR1 | 
| 179373 | Additional info for upgrade to Rel.4.6B | 
| 173814 | OCS: Known problems with Support Packages for Release 4.6 | 
| 147337 | Additional info for upgrade to Release 4.0B SR | 
| 97630 | OCS: Familiar problems with patches 3.1H-4.0B |