At this time up to creo 8.0.1 if parts fail to solidify in an assembly , f.e. by importing an assembly,
one needs to open each file and update the warning to ingore it, and save that part. Please note that ignoring the warning is not enough to save the part, you must also make save-able change ( f.e. setting a meaningless parameter to another value).
To avoid doing this , there should be an option to ignore all the solidification warnings in an assembly and have those changes saved in all underlying parts without further digging and grinding through the structure.