Pemetrexed Disodium and Erlotinib in Treating Patients With Advanced Non-Small Cell Lung Cancer or Other Solid Tumors

Inclusion Criteria: * For the phase I portion of the study patients must have cytologically or histologically proven advanced solid tumors for which there is no standard effective therapy available. For the phase II portion patients must have cytologically or histologically proven selected stage IIIB (pleural effusion) or IV NSCLC. Patients with NSCLC that have progressed or recurred after first-line therapy for stage IIIA or IIIB may also be considered. * For the phase II portion patients must have disease that has progressed or recurred after treatment with platinum-based therapy. * Any number of prior chemotherapy regimens are allowed for the phase I portion and no more than 1 previous treatment for advanced NSCLC is allowed for the phase II portion. * Patients must have measurable disease by RECIST criteria. Disease in previously irradiated sites is considered measurable if there is clear disease progression following radiation therapy. Patients with evaluable disease (bone metastases, pleural fluid, ascites, etc.) may be included in the phase I portion of the trial. * Patients must be 18 years of age or older. * Patients must have a performance status of 0-2 for phase I portion of study and a performance status of 0 -1 for the phase II portion of the trial. * Patients must have an estimated survival of at least 3 months. * Any prior chemotherapy that patients have received has to have been completed at least 4 weeks prior to start of treatment. For prior mitomycin chemotherapy a 6-week interval is required. Prior radiation must have been completed at least 2 weeks prior to start of therapy. Patients must have recovered from acute reversible side effects of prior chemotherapy regimens or radiotherapy to NCI-CTC \< grade 1 (excluding alopecia). * Patients must have adequate renal function as documented by a serum creatinine \< 1.5 mg/dl or a calculated creatinine clearance of \> 45 ml/min (see appendix for formula for calculating creatinine clearance). * Patients must have adequate liver function as documented by serum bilirubin \< 1.5 x ULN. AST must be \< 2.5 x institutional upper limit of normal. * Patients must have a pretreatment granulocyte count of \>1500/mm3 and platelet count of \>100 000/mm3. * Patients with asymptomatic treated brain metastasis (surgical resection or radiotherapy) may be included if they are neurologically stable and have been off steroids and anticonvulsants for at least 4 weeks. Because of the possibility of treatment related neurological toxicity it is difficult to evaluate for toxicity in the presence of symptomatic brain metastasis. * All patients must give voluntary written informed consent. * Patients must be able to take and retain oral medication. * Patients of reproductive potential must agree to use effective contraceptive method while on treatment and for 3 months afterwards as the effects of these drugs on the unborn fetus are unknown. * Patients on coumadin should have their INR monitored at least once per week or more frequently depending on the investigators judgement. There have been some case reports of increased INR when coumadin is co-administered with OSI-774/placebo. Exclusion Criteria: * Patients may not have previously received Pemetrexed or an EGFR-directed therapy. * Females can not be pregnant or breastfeeding as the effects of these drugs on the unborn fetus are unknown. Documentation of a negative serum pregnancy test is required for all women of reproductive potential. * Patients with symptomatic brain metastasis or still requiring steroids and anti-convulsants may not be included. * No other prior malignancy is allowed for the phase II portion except for the following: adequately treated basal cell or squamous cell skin cancer, in situ cervical cancer, adequately treated stage I or II cancer from which the patient is currently in complete remission, or any other cancer from which the patient has been disease-free for over five years. * Patients cannot take non-steroidal anti-inflammatory agents (NSAIDS) or salicylates 2 days prior and 2 days following (5 days pre and post for long-acting NSAIDS) administration of pemetrexed due to concerns of increased risk of renal toxicity. * Patients with clinically significant ophthalmologic abnormalities will be excluded. This includes severe dry eye syndrome, keratoconjunctivitis sicca, Sjogren's syndrome, severe exposure keratopathy, or other disorders that might increase the risk of corneal epithelial injury.