Something seems wrong with the CGIAR provider, I can reproduce your error with this code:
@Test
public void test_srtm_39_01() {
new CGIARProvider("tmp_cache").getEle(57.5, 10);
}
So for now your best option is using another elevation provider if you cannot skip elevation support altogether.
@karussell any idea what could be wrong with CGIAR here? The download url seems to be: http://srtm.csi.cgiar.org/wp-content/uploads/files/srtm_5x5/TIFF//srtm_39_01.zip