Andris is correct in asking this of you.
I have found the following on the SPSS Tech Support Website;
Problem Subject: Error 5263 and "Unable to open output file. The file was written by a later version of the software."
I have some files (.sav and .spo) that were created with SPSS Student version 13. Since upgrading to SPSS 15, when attempting to open the output (.spo) files, I receive the following error, in a Windows error dialog: "Unable to open output file. The file was written by a later version of the software." When attempting to open the data (.sav) files, I receive the following error in the SPSS output viewer: "Error 5263: The specified input data file is neither an SPSS data file nor an SPSS/PC+ data file." I have now attempted to open these files in SPSS 13, 14, and 15 with the same results. What could be causing this? Is there any way to salvage my files?
The file is most likely corrupt beyond repair.
The file is most likely corrupt beyond repair. In past reported cases of this error, there was no way to retrieve the data. We have been unable to replicate this behavior, and it is likely that a third-party software or hardware issue has lead to the corruption.
I hope this helps? Sorry if it does