THESE BOOTS WERE MADE FOR WALKIN'...AND MONICA JUST KEEPS ON TALKIN' ; TRUDIE STYLER AND MARLA SOKOLOFF GUEST STAR -- Chandler (Matthew Perry) is incensed when Monica (Courteney Cox Arquette) spends a fortune on a luscious pair of black boots but when she discovers that her sexy new footwear thrashes her feet, she puts on a brave front and walks on rather than admit that hubby knows best. Meanwhile, when a wide-eyed Phoebe (Lisa Kudrow) learns that Ross' (David Schwimmer) young son attends the same school as rock star Sting's son, she angles to meet the celebrity and get concert tickets -- until she afoul of his suspicious wife, Trudie Styler (as herself). In additon, Rachel (Jennifer Aniston) tries to mediate between an angry Joey (Matt LeBlanc) and his pregnant kid sister (guest star Marla Sokoloff, "The Practice").