I have been at customer site and faced following problem while using Admin tool to open RPD Online. The Oracle Support has a following document published to deal with this issue. It is an attempt to share it to wider audience.
Using the Admin tool to open the RPD Online produces an error:
[nQSError: 46036] Internal Assertion: Condition m_pFile->Read(bytes, sizeof(data)) == sizeof(data), file server\objectmodel\Src\SORpArchivePersistStream.cpp, line 373.
Reason and Resolution
The common reason for 'Internal Assertion' message is a version mismatch.
In order to check any version mismatches, log into Analytics as an Admin user and go to the Administration page. Expand the header, if needed, and verify you are on 22.214.171.124.1.
Then open the RPD in offline mode. Go to Help > About and verify the version is 126.96.36.199.1 and Repository version is 326.
As an example: Let's say the Administration tool version was 188.8.131.52.0 and RPD was 325. You will need to download the new version of the Administration Tool from the Analytics Home page. Upgrading the Admin tool to 184.108.40.206.1 solved the issue.
Oracle Support Link
I hope this copy and pasted information useful.