2003 Jetta 1.9L TDI w/hydraulic clutch and 5 speed manual transmission. Problem occured suddenly not gradually so must be failure rather than wear. When engine is running and clutch depressed, cannot shift into or out of any gear. With engine off, can shift thru all gears smoothly. With engine off, shift into any gear, then start engine and let clutch out, clutch engagement is smooth, everything is normal until next shift point. Can't shift unless engine is shut off, then shift is smooth, engine restarted and everything normal until next shift point. Same thing happens thru all gears. Clutch engages normally with no chatter. When stopped with engine running, no vehicle creep with transmission in gear, clutch fully depressed and brake released. Just cannot move shift lever when engine is running, but shift lever moves in and out of all gears smoothly when engine is off. Checked transmission cables support bracket - firmly attached ok. Checked brake fluid reservoir quantity - ok. No leaks observed in lines from brake fluid reservoir to clutch master cylinder or to clutch slave cylinder. All linkage from shift cables to various levers on transmission move smoothly without any binding or roughness. Any ideas would be greatly appeciated.