Setup of avast! program checks these libraries if they are installed. There is probably problem with them on your computer and program crashed when performing this test…
Message that have appeared is only warning to you - avast! will work with no problems without ODBC libraries…
Try to update system components using MDAC - it can be found at
http://www.microsoft.com/downloads/details.aspx?FamilyID=9ad000f2-cae7-493d-b0f3-ae36c570ade8&DisplayLang=en
and MS Jet
http://www.microsoft.com/data/download_Jet4SP3.htm