Does closing each report after opening each report solve it, as in:
DoCmd.OpenReport "rptAthensQuestionnaire", AcViewNormal, , _
"ParticipantID = Forms!frmPrintAllReports!txtSearch"
DoCmd.Close acReport,"rptAthensQuestionnaire"
DoCmd.OpenReport "rptEdinburghQuestionnaire", AcViewNormal, , _...