Protection Engine for Cloud Services

We have Protection Engine all set up for trial purposes, and everything works fine...

...until we try to scan a password-protected PDF file, which causes the following internal crash:

[OverflowException: Value was either too large or too small for a character.]
   System.Convert.ToChar(Int32 value) +6790142
   com.symantec.scanengine.api.Connection.Read(Stream resultStream, Policy requestPoicy) +622

[ScanException: Error while reading responseERR_RECIEVEING_RESPONSE]
   com.symantec.scanengine.api.Connection.Read(Stream resultStream, Policy requestPoicy) +1397
   com.symantec.scanengine.api.StreamScanRequestImpl.Finish(Stream resultFile) +387

[ScanException: ERR_RECIEVEING_RESPONSE]
   com.symantec.scanengine.api.StreamScanRequestImpl.Finish(Stream resultFile) +1016

The same file scans perfectly if I use the command-line tool on the server, so this must have something to do with the SDK implementation...? I haven't seen any other posts that address this specific issue.

In addition to the error code being misspelled, the message is not particularly helpful to me as an application developer. Since this is a System exception, my assumption is that this is some kind of bug in the SDK. Any ideas whether there's anything I can do on my end to work around this issue?

Upgrading the server version from 7.5.0.x to 7.5.1 appears to have fixed the problem.

(We did not have to upgrade to a new version of the SDK DLL.)