This is a Phase I open-label, dose-escalation safety study in subjects with refractory non hematologic malignancies. STA-5312 will be administered intravenously. Administration is anticipated to take 1 hour, although infusion time may be extended when appropriate with large infusion volumes. A treatment cycle is 4 weeks with a weekly infusion of STA 5312 for the first 3 weeks of each 4 week cycle. The planned treatment schedule is 2 cycles of STA-5312 treatment (8 weeks). Decisions regarding dose escalation and DLT determination will be made based on observations during the first cycle of therapy. Subjects who tolerate treatment may be eligible to continue receiving additional cycles of STA 5312 per the investigator's medical judgment. Evaluation of antitumor response will be performed after every 2 cycles of STA 5312 administration.