MIB load failure

When I try to use the MIB for my temperature & humidity monitoring device, OpManager 7 GA is throwing this error:

Error parsing MIB:us_an1graph_tf_mib_126.mib
Exception while loading MIB:Could not parse the file C:/PROGRA~1/ADVENT~1/ME/OPMANA~1/./mibs/us_an1graph_tf_mib_126.mib Couldn't resolve these MibNodes : { wtWebGraphThermHygroHTTP, wtWebGraphThermHygroDiag }

I have just downloaded the MIB straight from the manufacturer's website (http://www.wut.de/e-5wwww-15-inus-000.php - model is 57606) but it's still failing. I've attached the MIB as a text file.

Help would be greatly appreciated. We're testing OpManager as a potential replacement to our current monitoring solution and would like this sorted out!

thanks,
nickl