* FTSEurofirst 300 flat, Euro STOXX 50 slips 0.1 percent
* Traders cite concerns over weak company results, euro zone
* Bang & Olufsen falls 4 percent after posting losses
LONDON, Oct 10 (Reuters) - Concerns over weak corporate earnings and the euro zone debt crisis weighed on European stock markets on Wednesday, with traders saying key markets were set to fall further from highs reached last month.
The FTSEurofirst 300 index was flat at 1,095.71 points, while the euro zone Euro STOXX 50 index slipped by 0.1 percent to 2,469.54 points.
Worries over the euro zone debt crisis - and the struggles of countries such as Greece and Spain - were highlighted by the International Monetary Fund (IMF) on Wednesday, which called on European policymakers to act with urgency.
Although equity markets have rallied since July, when central banks such as the European Central Bank pledged new stimulus measures, the global economy is still weakening.
"The earnings are a problem. Companies aren't going to earn much when there's no growth," said Adrian Slack, head of equities at London-based Bastion Capital.
In a sign that earnings could disappoint, Danish luxury stereo and television maker Bang & Olufsen fell 4.4 percent on Wednesday after it reported a widening in pre-tax losses.
EURO ZONE WORRIES LINGER
According to Thomson Reuters Starmine data, earnings growth of companies in the pan-European STOXX 600 index will contract by 2.9 percent each year, on average, over the next five years.
The weak economic outlook was highlighted by the IMF on Wednesday, which said in a report that the euro zone's debt crisis had contributed to "very fragile" confidence in the global financial system.
Greece is struggling with the terms of its bailout deal, while uncertainty remains over the timing of any eventual Spanish request for a similar sovereign rescue package.
"The markets will be a little bit on the defensive, with concerns over Greece and Spain," said Richard Griffiths, associate director at Berkeley Futures.
The Euro STOXX 50 index has fallen more than 3 percent so far this week, and Bastion Capital's Slack said he would look to sell the index after it broke the 2,473 level, which some analysts said could push it down to 2,450 points.