We have had a similar problem and found that our repository on disk was being corrupted. HP thinks it was caused by incorrect privileges having been set for the user QTP runs under. The user that runs the "HP Quality Center" service (should be "Administrator" - singular, not plural) should have "Full Control" privilege to the entire HP directory uynder "Program Files".
All tests in QTP are identified by a number. The test name is actually only for the convenience of humans. The tests on the QC server (for QC 10.0) are stored under "C:\Program Files\HP\HP Quality Center Starter Edition\QCStarter\repository\qc\Default\<product-name>\tests". Every test is actually a folder with a number like "1234" in this "tests" directory. If you open the "1234" folder you should see some "Action<x>" directories - one for each action defined in your test. You should also see a .usr file, default.cfg, default.xls, parameters.mtr, and test.tsp. If any of all of these files are missing or have zero size, QTP won't be able to open the test. You could possible have more than one .usr file, but the .usr file named after the folder must have a non-zero size. Any other .usr files in that folder i would expect to have a size of 0.
To find out what the number associated with your test is, go into QC, select your test under "Test Plan". The "Details" tab in the right pane in your QC window will show "Test ID:". This is the number that QTP knows it by. That's the folder name you need to look in in your "test" directory on your QC server.
To see how your privs are set for Administrator on a folder in the HP directory, right-click on that directory, select Properties, then click on the "Security" tab. Select user "Administrator" and it should show that user having "Full Control" privilege to that folder.
All tests in QTP are identified by a number. The test name is actually only for the convenience of humans. The tests on the QC server (for QC 10.0) are stored under "C:\Program Files\HP\HP Quality Center Starter Edition\QCStarter\repository\qc\Default\<product-name>\tests". Every test is actually a folder with a number like "1234" in this "tests" directory. If you open the "1234" folder you should see some "Action<x>" directories - one for each action defined in your test. You should also see a .usr file, default.cfg, default.xls, parameters.mtr, and test.tsp. If any of all of these files are missing or have zero size, QTP won't be able to open the test. You could possible have more than one .usr file, but the .usr file named after the folder must have a non-zero size. Any other .usr files in that folder i would expect to have a size of 0.
To find out what the number associated with your test is, go into QC, select your test under "Test Plan". The "Details" tab in the right pane in your QC window will show "Test ID:". This is the number that QTP knows it by. That's the folder name you need to look in in your "test" directory on your QC server.
To see how your privs are set for Administrator on a folder in the HP directory, right-click on that directory, select Properties, then click on the "Security" tab. Select user "Administrator" and it should show that user having "Full Control" privilege to that folder.