Ben Okri supposedly creates a new form in his latest book, a loose collection of folk tales. He explains: "The following tales are properly 'stokus'. A stoku is an amalgam of short story and haiku. It is a story as it inclines towards a flash of a moment, insight, vision or paradox." Needless to say, a writer should not have to tell us what has been attempted. These are vague sketches - ill-formed, framed in generalised symbolic language, with only occasional moments of genuine poetry and insight.

Okri is justly celebrated for his fiction, which includes The Famished Road (1991), a Booker prize-winning novel of shocking power and freshness - a modern classic. He has often drawn on African folk tales for stylistic effects, with good results. His last novel, Starbook, was set in Africa, yet I doubt any African would recognise the magical kingdom he evokes in those pages. The longest story in this new book, "The Comic Destiny", could also be set in Africa, but it's a primordial place, a kind of Eden, although Adam and Eve seem to have hung around a bit too long. They become Old Man and Old Woman. Much of their time is spent torturing or berating their hapless servant, Pinprop - a figure who combines elements of Lucky and Pozzo from Waiting for Godot

But this is Beckett on hallucinogens. The dialogue is uninflected, often dreamy, as when Old Man and Old Woman chain Pinprop down in the woods:

"Now all we can do is wait," Old Woman said.
"Yes."
"And the boredom?"
"Oh, that. Let's enjoy that as well."
"Ah, yes."
"Yes to all that."
"Yes to everything."
"And to nothing."

It's difficult to enjoy the boredom on display here. Okri strains mightily, but the gold of meaning eludes him. Attempts to generate plot crumble into empty symbolic gestures, as when a young couple called New Man and New Woman appear. They argue by a tree that may represent the Tree of Knowledge, but they are . . . well, a chip off the old block. Both seem bored, ill-tempered, and Eden has become a leafy madhouse. The lively particulars that animated Okri's earlier fiction are oddly missing. "The Comic Destiny" is finally a rough outline for a fable that never gets written - not in any memorable way.

Thirteen brief tales follow, most of them parables of writing. One story takes us to "the magnificent grounds of our mysterious host". I wanted to shake Okri, saying: "Please. Make the place magnificent. Make the host mysterious. But don't tell us about the magnificence and the mystery." In "The Clock", the hapless speaker says: "Now I go through life not fixing my mind on anything, or anyone. There is a sort of freedom in this." But this is negative freedom, a refusal to engage, as if engagement would bring too much pain. In fact, most of these tales hover anxiously between "magic" and "realism", with the former winning out in every instance.

One thinks back to Okri's early novels, which centred on young men trapped in personal circumstances that mirrored the destruction of their country. In The Famished Road, the narrator was a spirit-child caught between the worlds of the living and the dead, while the grim realities lay everywhere about, glittering and terrible. In Dangerous Love, Okri took us deeply into the political and moral quagmire of Nigeria as its people tried to come to terms with a recent civil war. Here, unfortunately, Okri gives us nothing but hazy intimations of suffering in a mythical bombed-out city full of "devastated streets, broken bridges, flattened houses".

In "The Unseen Kingdom", about a fair that takes place in "the south of France, where books are treated like roses", I would actually for once have preferred a mythical kingdom. The setting is much too literal for the fantastic narrative that unfolds. In a hopelessly clichéd moment near the end, Okri writes: "The books breathe out a timeless peace and an eternal youth into the festival." Tales of Freedom was not among these books, I fear. A few times, for a few pages at a time, these stories occasionally stir to life. For the most part, however, Okri's fragile tales of freedom only gesture in the direction of meaning.

 Jay Parini's most recent book is Promised Land: Thirteen Books That Changed America (Doubleday)