just trying the trial version of v.1.2.705.7
got a 535mg avi, set a middle section selection, marked the beginning and end sections to delete, hit the Trim button. about 75% through the save i got "the data is invalid. HRESULT :0x8007000d (unspecified error hr=0x80004005)"
tried another much smaller file, worked ok. is my big file corrupted? if was an FLV i converted to AVI. it has, i believe a vid codec of MFZ0 lossless and audio ADPCM.