Alexander H. Cohen's "Parade of Stars," an ABC special tomorrow night at 9 on Channel 7, unfortunately plays like a two-hour Greatest Hits commercial. There are too many acts crammed, jammed and shoehorned into this tribute to the Palace Theater; a viewer is kept in a perpetual state of tease.

The program is also a medley of highly dubious editing decisions. Choicer moments like Shelley Winters' rowdy turn as Sophie Tucker fly by before they can even register, whereas mediocrities like Larry Kert's Jolson medley wear out welcomes but won't go away. Taped as a fundraiser before a dull-looking Manhattan audience (faces in the crowd include ABC network president James E. Duffy and ABC Entertainment chief Anthony D. Thomopoulos), the show pays tribute to vaudevillians who appeared at the Palace and to the musicals that have been harbored there since 1970.

Acts are tied together with a tiresome contrivance, backstage smalltalk by Jean Stapleton as a wardrobe lady, Eddie Albert as a stagehand, Edward Asner as a press agent and Michele Lee as a stage-struck ninny.

A show like this has two kinds of highlights--the genuine kind and the godawful campy kind. Among the former are a Gregory Hines dance routine (in homage to Bill Robinson), Dinah Shore's moving version of "Bill" (a la Helen Morgan) and a poignant ballad by Harry Belafonte, whose hair has grayed around an otherwise ageless face.

Among the lamentable pips are a surprisingly tubby Jeanne Moreau playing Sarah Bernhardt spouting French to an ornately coiffured Michael York, who looks as monkeyfaced as he did in "The Island of Dr. Moreau" (no relation to Jeanne). We're supposed to be pleased when Milton Berle halts his serious rendition of "September Song" to do some ancient physical schtick (assisted by Daniel J. Travanti). We are not.

Cohen, whose "Night of 100 Stars" was on the staggering side last season, merely staggers this time. But for all its disappointments, "Parade" is yet another reminder of the huge void left in the vast wasteland when the old TV variety shows died out.