Litecoin - mandatory-script-verify-flag-failed (Signature must be zero for failed CHECK(MULTI)SIG operation)
I am not 100% sure, if this also applies to Litecoin, as it is a clone of Bitcoin. But I understand the signature scheme is the same... So it should be possible to use openssl or any ECDSA library to check the signature. Therefor the double sea of the unsigned tx must be created, as per these steps by amaclin's answer:


  1) Remove input script from transaction 
  
  2) Replace it with the previous TX's pubkeyscript 
  
  3) Append SIGHASH_ALL 
  
  4) Hash it twice with SHA256


I try to replay it, and get these values:

sig:         3045022100ac91b8da716668553088da2da32c596a03973fffcbc36d2a7f3ecb8e93c3de07022040b7015c065e74d6f5fc30c9458c0631ddfb2d72feae3bb699c6ce835cd0ba54 
pubkey:      02d41b76393d5f82b1856343623974684ff2bf03b26ec6bc2d0391ae0768cd9ebd 
double hash: c54fa81808f1feef80298f232f00b42fa5d548b964d580026799b1bf5f431529


This returns an error in signature verification. This can have several root causes... You said, "after adjusting fee's and other network variables": the fees are related to the amounts in the output structure, and they are signed. At anytime something of the signed tx is changed, invalidates the signature. This might be the root cause ...
Can we see the unsigned transaction?