Open solution.
Search in all files for "perl510".
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Code:
C:\EQEmu\ServerCode\trunk\EQEmuServer\world\EQWParser.cpp(42):#pragma comment(lib, "perl510.lib")
C:\EQEmu\ServerCode\trunk\EQEmuServer\zone\embperl.cpp(33):#pragma comment(lib, "perl510.lib")
Change to perl512.