Ram,
In BOE XI 3.1 there is no such tool as UMT, it's called Import Wizard. The Import Wizard and a client tool that allows to migrate from previous versions of BOE 5.x / 6.x / XI / XIR2 / XI 3.x to BOE XI 3.1
In BI 4.x the UMT is a client tool that allows you to migrate from previous versions of BOE XIR2 SP4+ &/or BOE XI 3.1 SP2+ but from BI 4.x environment. Hopefully migration flow chart below will help.
For more in BOE XI 3.1 Import Wizard, see Admin Guide on XI 3.1
http://help.sap.com/businessobject/product_guides/boexir31SP3/en/xi31_sp3_bip_admin_en.pdf
For more on BI 4.2 UMT, see admin Guide for BI 4.2
http://help.sap.com/businessobject/product_guides/sbo42/en/sbo42sp2_bip_admin_en.pdf
Regards,
Ajay