Currently, there were two reports that AVG Free Edition may prevent YAPI to display and process signed documents. AVG shows Found Luhe.Exploit.PDF.H error preventing YAPI to access PDF document; YAPI consequently shows error E077. We were able to upload a PDF file to VirusTotal.com to prove false positive. Here is full report. Moreover, we haven’t seen this problem when running on computers protected by other than AVG anti-virus software.