Statement I is correct: Aniline does not undergo Friedel-Crafts alkylation or acylation reactions. This is because aniline is a basic compound (Lewis base) and reacts with the Lewis acid catalyst (such as anhydrous $AlCl_3$) to form a complex/salt. As a result, the nitrogen atom acquires a positive charge, acting as a strong deactivating group, thus preventing electrophilic substitution from occurring.

Statement II is also correct: Gabriel phthalimide synthesis is exclusively used for the preparation of pure aliphatic primary amines. It cannot be used to prepare aromatic primary amines like aniline because the required substrate, aryl halides, do not undergo nucleophilic substitution ($S_N2$) with the phthalimide anion under normal conditions.