VBA for Inserting Formula returning Run-time error '1004'

[blwager]

Hello,

I'm attempting to auto-fill a formula that has been converted to VBA.
Rather than going through the tedius method of manually rewriting the formula to be filled via VBA, I used the auto-record method.

Trouble is, rather than running smoothly it is returning the following error before even reaching the auto-fill portion of code:
"Run-time error '1004':
Application-defined or object-defined error"

All my single-line formulas are working just fine, but the following two are getting the same error (I recognize the 2nd is a mammoth. If the problem with the 1st is fixed, I should be able to repair the 2nd on my own):

    Range("O2").FormulaR1C1 = _
        "=IF('Verizon Cells & ACards'!RC13=""Current"",IF(SUMIFS('Verizon Cells & ACards'!C14,'Verizon Cells & ACards'!C3,'Verizon Cells & ACards'!RC3)=VLOOKUP('Cost by Decl'!R1C2,BillingPeriods,6)-VLOOKUP('Cost by Decl'!R1C2,BillingPeriods,5)+1,0,VLOOKUP('Cost by Decl'!R1C2,BillingPeriods,6)-VLOOKUP('Cost by Decl'!R1C2,BillingPeriods,5)+1-SUMIFS('Verizon Cells & ACards'!C14" & _
        "n Cells & ACards'!C3,'Verizon Cells & ACards'!RC3)),0)"

    Range("N2").FormulaR1C1 = _
        "=IF(ISBLANK(RC7),(VLOOKUP('Cost by Decl'!R1C2,BillingPeriods,6)-VLOOKUP('Cost by Decl'!R1C2,BillingPeriods,5))+1,IF(ISBLANK('Verizon Cells & ACards'!RC8),IF('Verizon Cells & ACards'!RC7<(VLOOKUP('Cost by Decl'!R1C2,BillingPeriods,5)),VLOOKUP('Cost by Decl'!R1C2,BillingPeriods,6)-VLOOKUP('Cost by Decl'!R1C2,BillingPeriods,5)+1,IF('Verizon Cells & ACards'!RC7>(VLOOKUP" & _
        "y Decl'!R1C2,BillingPeriods,6)),0,VLOOKUP('Cost by Decl'!R1C2,BillingPeriods,6)-'Verizon Cells & ACards'!RC7+1)),IF('Verizon Cells & ACards'!RC8<VLOOKUP('Cost by Decl'!R1C2,BillingPeriods,5),0,IF('Verizon Cells & ACards'!RC8>VLOOKUP('Cost by Decl'!R1C2,BillingPeriods,6),IF('Verizon Cells & ACards'!RC7>VLOOKUP('Cost by Decl'!R1C2,BillingPeriods,6),0,IF('Verizon Cells" & _
        "'!RC7<(VLOOKUP('Cost by Decl'!R1C2,BillingPeriods,5)),VLOOKUP('Cost by Decl'!R1C2,BillingPeriods,6)-VLOOKUP('Cost by Decl'!R1C2,BillingPeriods,5)+1,VLOOKUP('Cost by Decl'!R1C2,BillingPeriods,6)-'Verizon Cells & ACards'!RC7+1)),IF('Verizon Cells & ACards'!RC7>VLOOKUP('Cost by Decl'!R1C2,BillingPeriods,6),0,IF('Verizon Cells & ACards'!RC7<(VLOOKUP('Cost by Decl'!R1C2," & _
        "riods,5)),'Verizon Cells & ACards'!RC8-(VLOOKUP('Cost by Decl'!R1C2,BillingPeriods,5)),'Verizon Cells & ACards'!RC8-'Verizon Cells & ACards'!RC7+1))))))"

Any help will be greatly appreciated. And before anyone offers it, I did double-check that it' susing the ..." & _" syntax for long vba code. I couldn't find anything more for multiple lines of code in a formula.