Austria Hungary's geographic position in the center of Europe made it especially difficult to send men and supplies out of the continent and into potential colonies. More importantly, the empire was extremely polyglot and ethnically diverse. The Austrian half, or Cisleithania contained Czechs, Poles, Slovenes, Italians, Croats, and Ruthenians besides the ruling class of German-Austrians. The Hungarian half, or Transleithania had Slovaks, Romanians, and Croats. With growing nationalistic sentiments among its minorities, exemplified by and culminating in the Revolutions of 1848, the Habsburgs had to devote manpower and resources to suppressing (or compromising with) its subject minorities in order to keep their empire and holdings intact. This is exemplified in the Ausgleich or Compromise of 1867, in which the Dual Monarchy was formed out of the Austrian Empire and Hungary given an elevated position within the empire. Thus, Austria-Hungary understandably needed to be focused on internal politics and unrest rather than spending manpower and resources on some distant colonial venture. This is in contrast to one of the newer colonial powers like Germany, which despite having its own large Polish minority, was still much more ethnically and linguistically homogeneous. I'm sure there are other major reasons for this such as economical and geopolitical reasons too, though ethnic nationalist tensions is probably one of the larger ones.

The empire as a European Great Power did send representatives to the Berlin Conference of 1884-85 which essentially saw the African continent partitioned between the European colonial powers, and the recognition and settlement of territorial claims and rights within the continent. As a signatory, it confirmed that A-H would be able to take part in free trade in the Congo Basin and Lake Malawi regions, as well as well as free traffic in the Congo and Niger rivers. Even if Austria-Hungary did not claim any colonial possessions in Africa, it would have at least asserted itself in taking part in negotiations among the colonial powers rather than excluding and isolating itself diplomatically.

Austria Hungary did send a small force of men as part of the Eight-Nation Alliance that put down the Boxer Rebellion though, and their concession in Tianjin as a reward was their only territorial possession outside Europe. Though personally, I think one of the few reasons the Austro-Hungarians did so was to prevent from becoming diplomatically obsolete and the need to demonstrate its (though probably diminishing) status as a Great Power by projecting its power internationally.