Contradiction with Romans 7:6
This verse speaks of being delivered from the law and serving in newness of spirit, whereas Psalms 119:45 talks about walking at liberty by seeking the precepts which are the law.
Romans 7:6: But now we are delivered from the law, that being dead wherein we were held; that we should serve in newness of spirit, and not [in] the oldness of the letter. [that being...: or, being dead to that]
Contradiction with Galatians 5:18
This verse mentions being led by the Spirit and not being under the law, in contrast to Psalms 119:45 which associates liberty with seeking the law.
Galatians 5:18: But if ye be led of the Spirit, ye are not under the law.
Contradiction with 2 Corinthians 3:6
This verse states that "the letter killeth, but the spirit giveth life," whereas Psalms 119:45 suggests that following the law (precepts) grants freedom.
2 Corinthians 3:6: Who also hath made us able ministers of the new testament; not of the letter, but of the spirit: for the letter killeth, but the spirit giveth life. [giveth life: or, quickeneth]