I'll give you a copy of the report, but I can't guarantee its accuracy.

Literal

Report [possessive-の] copy [object-を] give-[volitional-polite-ましょう], however its accuracy [topic-は] guarantee cannot

写し (うつし) = a copy (from 写す, to copy/transcribe). あげましょう offers with the polite volitional — 'let me give you.' しかし = however (formal connective). 保証できません = cannot guarantee.