a single-member LLC, that did not elect corporate taxation, is a disregarded entity for federal income tax purposes. it does not file its own tax return. Rather the results are included in you 1040. What you need to do in this case is determine your overall tax liabilty. Pay it on or before 4/15 (some exceptions apply). if you can't file by 4/15 submit an extension Form 4868, but your taxes are still due as noted above.
