Iran - no
Um, from the article:
weapons to Bosnia: "the arming of the Bosnian Muslims by Iran and Saudi Arabia ... From 1993 to 1996 there was an influx of weapons and military advisers into Bosnia, largely organised by Iranian and Saudi officials."
fighters to Bosnia: "'eight flights a month packed with thousands of tons of arms and ammunition either originating in Iran or purchased and shipped with Iranian backing' arrived in Zagreb destined for the Bosnian Muslims and also for Croats; and Iran played a role in 'station[ing] from 3,000 to 4,000 revolutionary guards [Mujihadeen] in Bosnia'"
Chechnya: "During this period, Saudi Arabia, Lebanon and Iran also played a role in 'funding the spread of Islamist armed groups in the region' (12). Iranian and Saudi officials seem to have taken the USA's 'green light' to mean that the sponsorship of Mujihadeen forces across state borders was as legitimate in Chechnya as it was in the Balkans."
Why are you disputing Iran's involvement in supporting international Islamic mujihadeen?
In Bosnia, Iran was involved. I doubt that it is involved in Chechnya - Russian/Iranian relations in Caucasus/Caspian Sea are too good for that. I remember that Iranian mullahs were traveling in southern Russia to preach loyalty to Russian government among Muslims.