Please make some changes in Java files.
1.Navigate to the ...\Program Files\IMC\deploy folder. Locate the JavaService application
2. Right-click and rename as JavaService_32
3. Navigate to the imc V7.2 download folder. Navigate to windows\install\components\common\deploy folder and copy the JavaService64 application file.
4. Copy the JavaService64 application file into the ...\Program Files\IMC\deploy folder and rename it to JaveService.
5. Navigate to administrative tools > Services, right-click HP imc Server and select Start. The status of the HP imc Server should change to Running.
6.Start the imc Deployment ASgent and select the install button. Specify the path for imc V7.3 upgarde and select ok.
Now the JavaService file is correct, the upgrade to imc V7.3 should complete successfully.